Supplemental Prospectus (Form 424B5)

Filed Pursuant to Rule 424(b)(5)
Registration No. 333-290735

TABLE OF CONTENTS

PROSPECTUS SUPPLEMENT

PROSPECTUS DATED OCTOBER 6, 2025

ABOUT THIS PROSPECTUS SUPPLEMENT

This document is in two parts. The first part is this prospectus supplement, which describes the specific terms of this offering and also adds to and updates information contained in the accompanying prospectus The second part contains an accompanying primary base prospectus relating to sales of shares of Class A common stock and other securities by Solaris Energy Infrastructure, Inc. and gives more general information, some of which may not apply to this offering. Generally, when we refer to the "prospectuses," we are referring to this prospectus supplement and the accompanying base prospectus combined. Unless otherwise indicated, capitalized terms used but not defined herein have the meaning assigned to them in the registration statement of which this prospectus supplement forms a part. You should read the entire prospectus supplement, as well as the accompanying base prospectus and the documents incorporated by reference that are described under "Incorporation of Certain Information by Reference" in this prospectus supplement. To the extent that any statement we make in this prospectus supplement is inconsistent with statements made in the accompanying base prospectus or any documents incorporated by reference herein, you should rely on the information contained in this prospectus supplement, which will be deemed to modify or supersede those made in the accompanying prospectus or documents incorporated by reference herein or therein.

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You should rely only on the information included or incorporated by reference in this prospectus supplement and the accompanying base prospectus prepared by us or on behalf of us or to which we have referred you. Neither we, the Underwriter nor any of our or its representatives have authorized any other person to provide you with information different from that included or incorporated by reference in this prospectus supplement and the accompanying base prospectus. If anyone provides you with different or inconsistent information, you should not rely on it. Neither we nor the Underwriter are making an offer to sell these securities in any jurisdiction where an offer or sale is not permitted. The information in this prospectus supplement, and the information in the accompanying base prospectus or contained in any document incorporated by reference is accurate only as of the date of such prospectus or document incorporated by reference, regardless of the time of delivery of this prospectus supplement or any sale of our Class A common stock. Our business, financial condition, results of operations and prospects may have changed since that date.

This prospectus contains forward-looking statements that are subject to a number of risks and uncertainties, many of which are beyond our control. Please read the sections entitled "Risk Factors" and "Cautionary Statement Regarding Forward-Looking Statements."

TRADEMARKS AND TRADE NAMES

We own or have rights to various trademarks, service marks and trade names that we use in connection with the operation of our business. This prospectus may also contain trademarks, service marks and trade names of third parties, which are the property of their respective owners. Our use or display of third parties' trademarks, service marks, trade names or products in this prospectus is not intended to and does not imply a relationship with us or an endorsement or sponsorship by or of us. Solely for convenience, the trademarks, service marks and trade names referred to in this prospectus may appear without the ^®, ^™ or SM symbols, but such references are not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights or the right of the applicable licensor to these trademarks, service marks and trade names.

CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This prospectus supplement, the accompanying prospectus and the documents incorporated by reference herein include "forward-looking statements" within the meaning of Section 27A of the Securities Act of 1933, as amended (the "Securities Act") and Section 21E of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), which involve risks, uncertainties and assumptions. Statements that are predictive in nature, that depend upon or refer to future events or conditions or that include the words "believe," "expect," "anticipate," "intend," "estimate," "could," "may," "continue," "predict," "potential," "plan," "will," "should" and other expressions that are predictions of or indicate future events and trends and that do not relate to historical matters identify forward-looking statements. Our forward-looking statements include statements about our business strategy, our industry, our future profitability, our expected capital expenditures and the impact of such expenditures on our performance, management changes, current and potential future long-term contracts, our capital programs and our future business and financial performance. In addition, our forward-looking statements address the various risks and uncertainties associated with extraordinary market environments, and the expected impact on our businesses, results of operations, and earnings.

A forward-looking statement may include a statement of the assumptions or bases underlying the forward-looking statement. We believe that we have chosen these assumptions or bases in good faith and that they are reasonable. You are cautioned not to place undue reliance on any forward-looking statements. You should also understand that it is not possible to predict or identify all such factors and should not consider the following list to be a complete statement of all potential risks and uncertainties. Factors that could cause our actual results to differ materially from the results contemplated by such forward-looking statements include:

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All forward-looking statements speak only as of the date of this prospectus supplement. You should not place undue reliance on our forward-looking statements. Although forward-looking statements reflect our good faith beliefs at the time they are made, forward-looking statements involve known and unknown risks, uncertainties and other factors, including the factors described under Part I, Item 1A. "Risk Factors" of our Annual Report on Form 10-K for the year ended December 31, 2024, under Part II, Item 1A. "Risk Factors" of our Quarterly Reports on Form 10-Q for the three months ended March 31, 2025 and June 30, 2025, and in our other filings with the United States Securities and Exchange Commission (the "SEC"), which may cause our actual results, performance or achievements to differ materially from anticipated future results, performance or achievements expressed or implied by such forward-looking statements. We undertake no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events, changed circumstances or otherwise, unless required by law.

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RISK FACTORS

An investment in our securities involves a high degree of risk. You should carefully consider the risks described below, as well as those risk factors described under the heading "Risk Factors" in our most recent Annual Report on Form 10-K for the year ended December 31, 2024 and our Quarterly Reports on Form 10-Q for the three months ended March 31, 2025 and June 30, 2025, each of which is incorporated by reference herein, together with all of the other information included in this prospectus supplement, the accompanying base prospectus and the documents we incorporate by reference, in evaluating an investment in our securities. Our business, prospects, financial condition or operating results could be harmed by any of these risks, as well as other risks not currently known to us or that we currently consider immaterial. The trading price of our Class A common stock could decline due to any of these risks, and, as a result, you may lose all or part of your investment. Before deciding whether to invest in our securities, you should also refer to the other information contained in or incorporated by reference into this prospectus supplement, including the section entitled "Cautionary Note Regarding Forward-Looking Statements."

Risks Related to this Offering

The offer and sale of our shares of Class A common stock in this offering, which such offer and sale are being executed to facilitate the initial hedging transactions by the Convertible Arbitrage Investors subscribing for our Notes in the Concurrent Notes Offering, may have a negative effect on the market price of our Class A common stock.

In connection with the Concurrent Notes Offering,    shares of our Class A common stock are being offered by the Underwriter, on behalf of itself and/or its affiliates pursuant to this prospectus supplement to facilitate hedging transactions by the Convertible Arbitrage Investors subscribing for our Notes. We have been advised that the shares of Class A common stock sold by the Underwriter in this offering will be borrowed from non-affiliate third parties, and will be: (x) purchased by the Underwriter from certain Convertible Arbitrage Investors who have sold them short to such Underwriter in connection with the Concurrent Notes Offering and/or (y) sold short by the Underwriter to facilitate concurrent privately negotiated transactions between the Underwriter (or its affiliates) with certain Convertible Arbitrage Investors seeking a short exposure to our shares of Class A common stock through a derivative.

The number of shares of our Class A common stock subject to this offering will depend on what portion of Convertible Arbitrage Investors desire to hedge their investment in the Notes, and is expected to be no greater than commercially reasonable initial short positions of the Convertible Arbitrage Investors in the Notes which are being established to facilitate their market risk hedging with respect to the Notes they acquire in the Concurrent Notes Offering. It is possible, however, that investors in the Notes in the Concurrent Notes Offering may short sell additional shares of our Class A common stock shortly after the pricing of this offering. Such additional sales could have the effect of causing the market price of our shares of Class A common stock to be lower than it would have been absent such selling.

In addition, a portion of the shares of our Class A common stock sold short by the Underwriter in this offering will be sold to facilitate concurrent privately negotiated transactions between the Underwriter (or its affiliates) with certain Convertible Arbitrage Investors seeking a short exposure to shares of our Class A common stock through a derivative. The Underwriter (or its affiliates) acting as dealer on such privately negotiated transactions may modify, enter into or unwind additional privately negotiated transactions (including derivative transactions) and/or purchase or sell shares of our Class A common stock or other securities of ours in secondary market transactions at any time following the pricing of the Concurrent Notes Offering. For example, in connection with any cash settlement of any such derivative transaction, the dealer may purchase shares of our Class A common stock and Convertible Arbitrage Investors may sell shares of our Class A common stock, which could affect the trading price of our Class A common stock at the time. This offering and any privately negotiated transactions relating to our Class A common stock, including derivatives with the Underwriter or its

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affiliates could cause more sales of our Class A common stock while the Notes are outstanding than there would have been otherwise had we not consummated this offering.

Risks Related to the Concurrent Notes Offering

The issuance of shares of our Class A common stock upon conversion of Notes will dilute the ownership interests of our stockholders and could depress the trading price of our Class A common stock.

Upon conversion of the Notes being offered in the Concurrent Notes Offering, we will satisfy part or all of our conversion obligations in shares of our Class A common stock, unless we elect to settle conversions solely in cash. The issuance of shares of our Class A common stock upon conversion of the Notes will dilute the ownership interests of our stockholders, which could depress the trading price of our Class A common stock. In addition, the market's expectation that conversions may occur could depress the trading price of our Class A common stock even in the absence of actual conversions. Moreover, the expectation of conversions could encourage the short selling of our Class A common stock, which could place further downward pressure on the trading price of our Class A common stock.

Hedging activity by investors in the Concurrent Notes Offering could depress the trading price of our Class A common stock.

While this offering is expected to initially facilitate the establishment of short positions in our Class A common stock by certain Convertible Arbitrage Investors to hedge the market risk of their investments in the Notes concurrently with, or shortly, after the pricing of the Concurrent Notes Offering, neither we nor the Underwriter will control any transactions that investors in the Notes may enter into at any time, including purchases and sales of our Class A common stock. We expect that many investors in the Notes being offered in the Concurrent Notes Offering, including potential purchasers of the Notes following the Concurrent Notes Offering, will seek to employ a convertible note arbitrage strategy. Under this strategy, investors typically short sell a certain number of shares of our Class A common stock and adjust their short position over time while they continue to hold the convertible notes. Investors may also implement this type of strategy by entering into swaps on our Class A common stock in lieu of, or in addition to, short selling shares of our Class A common stock. This market activity, or the market's perception that it will occur, could depress the trading price of our Class A common stock.

Provisions in the indenture that will govern the Notes in the Concurrent Notes Offering could delay or prevent an otherwise beneficial takeover of us.

Certain provisions in the Notes and the indenture that will govern the Notes in the Concurrent Notes Offering (the "indenture") could make a third party attempt to acquire us more difficult or expensive. For example, if a takeover constitutes a "fundamental change" (which will be defined in the indenture that will govern the Notes to include certain change of control events and the delisting of shares of our Class A common stock), then, investors of the Notes in the Concurrent Notes Offering will have the right to require us to repurchase their convertible Notes for cash. In addition, if a takeover constitutes a "make-whole fundamental change" (which will be defined in the indenture to include, among other events, fundamental changes and certain additional business combination transactions), then we may be required to temporarily increase the conversion rate for the Notes. In either case, and in other cases, our obligations under the Notes and the indenture could increase the cost of acquiring us or otherwise discourage a third party from acquiring us or removing incumbent management, including in a transaction that holders of our Class A common stock may view as favorable.

We may be unable to raise the funds necessary to repurchase the Notes being offered in the Concurrent Notes Offering for cash following a fundamental change or to pay any cash amounts due upon maturity or conversion of the Notes, and our other indebtedness limits our ability to repurchase the Notes or to pay any cash amounts due upon their maturity or conversion.

Investors in the Notes may, subject to a limited exception, require us to repurchase their Notes following a "fundamental change" (which will be defined in the indenture to include certain change-of-control events and the

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delisting of shares of our Class A common stock) at a cash repurchase price generally equal to the principal amount of the Notes to be repurchased, plus accrued and unpaid interest, if any. In addition, upon conversion, we will satisfy part or all of our conversion obligation in cash unless elect to settle conversions solely in shares of our Class A common stock. We may not have enough available cash or be able to obtain financing at the time we are required to repurchase the Notes or pay any cash amounts due upon conversion. In addition, applicable law, regulatory authorities and the agreements governing our other indebtedness may restrict our ability to repurchase the Notes or pay any cash amounts due upon conversion. For example, we expect to fund payments due on the Notes from corresponding payments due to us under the intercompany convertible note to be issued by Solaris LLC to us. Our Revolving Credit Facility will prohibit Solaris LLC from making payments to us under the intercompany convertible note except to provide for regularly scheduled interest payments, provided no events of default exists under the Revolving Credit Facility, as applicable, or would result therefrom, and except for certain other payments in equity interests. Accordingly, we may not have access to funds from Solaris LLC to repurchase the Notes for cash following a fundamental change or to pay any cash amounts due upon conversion of the Notes. We may seek to obtain a waiver under the Revolving Credit Facility to permit these payments, but we cannot assure you that we will able to obtain such a waiver. Our failure to repurchase the Notes or pay any cash amounts due upon conversion when required will constitute a default under the indenture that will govern the Notes. A default under the indenture or the fundamental change itself could also lead to a default under agreements governing our other indebtedness, which may result in that other indebtedness becoming immediately payable in full. We may not have sufficient funds to satisfy all amounts due under the other indebtedness and the Notes.

The 2030 notes have similar conversion and repurchase provisions as the Notes we are offering in the Concurrent Notes Offering, which exacerbates the risks described above.

The indenture that governs our existing 4.75% senior convertible notes due 2030 (the "2030 notes") and the indenture that will govern the Notes will not restrict us from incurring additional indebtedness, and the incurrence of the convertible Notes and any additional indebtedness could limit the cash flow available for our operations, expose us to risks that could adversely affect our business, financial condition and results of operations.

As of June 30, 2025, we had approximately $552.0 million principal amount of consolidated indebtedness for borrowed money. We will incur $600.0 million (or, if the underwriters of the Concurrent Notes Offering fully exercise their option to purchase additional notes, $690.0 million) principal amount of additional indebtedness as a result of the Concurrent Notes Offering (and we intend to use a portion of the net proceeds from the Concurrent Notes Offering to repay $320.9 million outstanding principal amount under the Term Loan Agreement) as a result of the Concurrent Notes Offering. The indenture that governs the 2030 notes does not and the indenture that will govern the Notes will not contain any meaningful restrictive covenants and will not prohibit us or our subsidiaries from incurring additional indebtedness in the future. Accordingly, we may incur a significant amount of additional indebtedness following the Concurrent Notes Offering, if it is completed. The incurrence of indebtedness could have significant negative consequences for our stockholders and our business, results of operations and financial condition by, among other things:

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Our business may not generate sufficient funds, and we may otherwise be unable to maintain sufficient cash reserves, to pay amounts due under our indebtedness, and our cash needs may increase in the future. In addition, our Revolving Credit Facility contains, and any future indebtedness that we may incur may contain, financial and other restrictive covenants that limit our ability to operate our business, raise capital or make payments under our other indebtedness. If we fail to comply with these covenants or to make payments under our indebtedness when due, then we would be in default under that indebtedness, which could, in turn, result in that and our other indebtedness becoming immediately payable in full.

The accounting method for the Notes and the capped call transactions could adversely affect our reported financial condition and results.

The accounting method for reflecting the Notes on our balance sheet, accruing interest expense for the Notes and reflecting the underlying shares of our Class A common stock in our reported diluted earnings per share may adversely affect our reported earnings and financial condition.

In accordance with applicable accounting standards, we expect that the Notes we are offering pursuant to the Concurrent Notes Offering will be reflected as a liability on our balance sheets, with the initial carrying amount equal to the principal amount of the Notes, net of issuance costs. The issuance costs will be treated as a debt discount for accounting purposes, which will be amortized into interest expense over the term of the Notes. As a result of this amortization, the interest expense that we expect to recognize for the Notes for accounting purposes will be greater than the cash interest payments we will pay on the Notes, which will result in lower reported income.

In addition, we expect that the shares of Class A common stock underlying the Notes will be reflected in our diluted earnings per share using the "if converted" method. Under that method, diluted earnings per share would generally be calculated assuming that all the Notes were converted solely into shares of our Class A common stock at the beginning of the reporting period, unless the result would be anti-dilutive. The application of the if-converted method may reduce our reported diluted earnings per share, and accounting standards may change in the future in a manner that may adversely affect our diluted earnings per share.

Furthermore, if any of the conditions to the convertibility of the Notes is satisfied, then we may be required under applicable accounting standards to reclassify the liability carrying value of the Notes as a current, rather than a long-term, liability. This reclassification could be required even if no investors of Notes in the Concurrent Notes Offering convert their Notes and could materially reduce our reported working capital.

We expect that the cost of entering into the capped call transactions to be reflected as a reduction in paid-in capital in the stockholders' equity section of our balance sheet.

However, we have not reached a final determination regarding the accounting treatment for the Notes or the capped call transactions, and the description above is preliminary. Accordingly, we may account for the Notes in a manner that is significantly different than described above.

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USE OF PROCEEDS

We will not receive any of the proceeds from the short sale of the shares of our Class A common stock by the Underwriter in this offering. No new shares of Class A common stock will be issued in this offering.

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THE CONCURRENT NOTES OFFERING AND CAPPED CALL TRANSACTIONS

Concurrently with this offering, we are offering    % convertible senior notes due 2031, which we refer to as the Notes, in an aggregate principal amount of $600.0 million. We have granted the underwriters of the Notes in the Concurrent Notes Offering an option to purchase, for settlement within a period of 13 days from, and including, the date the Notes in the Concurrent Notes Offering are first issued, up to an additional $90.0 million principal amount of Notes solely to cover over-allotments.

We estimate that the net proceeds to us from the Concurrent Notes Offering, if it is consummated, will be approximately $     million (or approximately $     million if the underwriters of Notes in the Concurrent Notes Offering fully exercise their option to purchase additional Notes), after deducting the underwriters' discounts and commissions and our estimated offering expenses. We intend to use approximately $     million (or approximately $     million if the underwriters fully exercise their option to purchase additional notes) of the net proceeds to fund the cost of entering into the capped call transactions described below. We expect to use the remainder of the net proceeds to purchase from Solaris LLC, our operating subsidiary, a subordinated convertible note to be issued by Solaris LLC with substantially similar economic terms as the notes (also taking into account the effect of the capped call transactions), and Solaris LLC expects to use such net proceeds to (i) repay the outstanding principal amount of approximately $320.9 million (plus accrued and unpaid interest and any make-whole or other prepayment premium) under and terminate the Term Loan Agreement and (ii) fund growth capital for additional power generation equipment, including new natural gas turbines and complementary "balance of plant" electrical equipment, to support customer activity. If the underwriters of Notes in the Concurrent Notes Offering exercise their option to purchase additional Notes, then we intend to transfer the additional net proceeds to Solaris LLC in exchange for an increase to the note it previously issued to us.

The Concurrent Notes Offering is being made pursuant to a separate prospectus supplement and accompanying base prospectus (and not pursuant to this prospectus supplement nor the accompanying base prospectus). The completion of this offering is contingent upon the completion of the Concurrent Notes Offering, and the completion of the Concurrent Notes Offering is contingent upon the completion of this offering. This prospectus supplement and the accompanying base prospectus do not constitute an offer to sell, or the solicitation of an offer to buy, any of the Notes, or the shares of Class A common stock, if any, issuable upon conversion of the Notes, that we are offering in the Concurrent Notes Offering.

The Notes will be our senior, unsecured obligations and will accrue interest at a rate of    % per annum, payable semi-annually in arrears on April 1 and October 1 of each year, beginning on April 1, 2026. The Notes will mature on October 1, 2031, unless earlier repurchased, redeemed or converted. Before July 1, 2031, noteholders will have the right to convert their Notes only upon the occurrence of certain events. From and after July 1, 2031, noteholders may convert their Notes at any time at their election until the close of business on the second scheduled trading day immediately before the maturity date. We will settle conversions by paying or delivering, as applicable, cash, shares of our Class A common stock or a combination of cash and shares of our Class A common stock, at our election. The initial conversion rate is    shares of Class A common stock per $1,000 principal amount of Notes, which represents an initial conversion price of approximately $    per share of Class A common stock. The conversion rate and conversion price will be subject to adjustment upon the occurrence of certain events. If a "make-whole fundamental change" (which will be defined in the indenture that will govern the Notes to include certain business combination transactions involving us, the delisting of our Class A common stock and the calling of the Notes for redemption) occurs, then we will in certain circumstances increase the conversion rate for a specified period of time. In the case of a make-whole fundamental change resulting from the calling of any Notes for redemption, the increased conversion rate, if any, will apply only to the Notes called (or deemed to be called) for redemption.

The Notes will be redeemable, in whole or in part (subject to certain limitations described below), at our option at any time, and from time to time, on or after October 2, 2028 and on or before the 40th scheduled trading

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day immediately before the maturity date, at a cash redemption price equal to the principal amount of the Notes to be redeemed, plus accrued and unpaid interest, if any, to, but excluding, the redemption date, but only if the last reported sale price per share of our Class A common stock exceeds 130% of the conversion price for a specified period of time. However, we may not redeem less than all of the outstanding Notes unless at least $100.0 million aggregate principal amount of Notes are outstanding and not called for redemption as of the time we send the related redemption notice.

If a "fundamental change" (which will be defined in the indenture that will govern the Notes to include certain change-of-control events and the delisting of our Class A common stock) occurs, then, subject to a limited exception, noteholders may require us to repurchase their Notes for cash. The repurchase price will be equal to the principal amount of the Notes to be repurchased, plus accrued and unpaid interest, if any, to, but excluding, the applicable repurchase date.

In connection with the pricing of the Notes, we expect to enter into privately negotiated capped call transactions with one or more dealers that are underwriters in the Concurrent Notes Offering or their affiliates and/or other financial institutions. The capped call transactions are expected generally to reduce potential dilution to our Class A common stock upon any conversion of the Notes and/or offset any potential cash payments we are required to make in excess of the principal amount of converted Notes, as the case may be, with such reduction and/or offset subject to a cap. If the underwriters exercise their option to purchase additional notes, then we expect to enter into additional capped call transactions with the option counterparties. In connection with establishing their initial hedges of the capped call transactions, the option counterparties or their respective affiliates expect to enter into various derivative transactions with respect to our Class A common stock and/or purchase shares of our Class A common stock concurrently with or shortly after the pricing of the Notes. This activity could increase (or reduce the size of any decrease in) the market price of our Class A common stock at that time. In addition, the option counterparties or their respective affiliates may modify their hedge positions by entering into or unwinding various derivatives with respect to our Class A common stock and/or purchasing or selling our Class A common stock or other securities of ours in secondary market transactions following the pricing of the Notes and from time to time prior to the maturity of the Notes (and are likely to do so (x) following any conversion of the Notes, any repurchase of the Notes by us on any fundamental change repurchase date or any redemption date, (y) following any other repurchase of the Notes if we elect to unwind a corresponding portion of the capped call transactions in connection with such repurchase and (z) if we otherwise elect to unwind all or a portion of the capped call transactions). This activity could also cause or avoid an increase or a decrease in the market price of our Class A common stock.

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CERTAIN ERISA CONSIDERATIONS

The following is a summary of certain considerations associated with the acquisition and holding of shares of common stock by employee benefit plans that are subject to Title I of the Employee Retirement Income Security Act of 1974, as amended ("ERISA"), plans, individual retirement accounts and other arrangements that are subject to Section 4975 of the Code (as defined herein) or employee benefit plans that are governmental plans (as defined in Section 3(32) of ERISA), certain church plans (as defined in Section 3(33) of ERISA), non-U.S. plans (as described in Section 4(b)(4) of ERISA) or other plans that are not subject to the foregoing but may be subject to provisions under any other federal, state, local, non-U.S. or other laws or regulations that are similar to such provisions of ERISA or the Code (collectively, "Similar Laws"), and entities whose underlying assets are considered to include "plan assets" of any such plan, account or arrangement (each, a "Plan").

This summary is based on the provisions of ERISA and the Code (and related regulations and administrative and judicial interpretations) as of the date of this prospectus supplement. This summary does not purport to be complete, and no assurance can be given that future legislation, court decisions, regulations, rulings or pronouncements will not significantly modify the requirements summarized below. Any of these changes may be retroactive and may thereby apply to transactions entered into prior to the date of their enactment or release. This discussion is general in nature and is not intended to be all inclusive, nor should it be construed as investment or legal advice.

General Fiduciary Matters

ERISA and the Code impose certain duties on persons who are fiduciaries of a Plan subject to Title I of ERISA or Section 4975 of the Code (an "ERISA Plan") and prohibit certain transactions involving the assets of an ERISA Plan and its fiduciaries or other interested parties. Under ERISA and the Code, any person who exercises any discretionary authority or control over the administration of an ERISA Plan or the management or disposition of the assets of an ERISA Plan, or who renders investment advice for a fee or other compensation to an ERISA Plan, is generally considered to be a fiduciary of the ERISA Plan.

In considering an investment in shares of common stock with a portion of the assets of any Plan, a fiduciary should consider the Plan's particular circumstances and all of the facts and circumstances of the investment and determine whether the acquisition and holding of shares of common stock is in accordance with the documents and instruments governing the Plan and the applicable provisions of ERISA, the Code, or any Similar Law relating to the fiduciary's duties to the Plan, including, without limitation:

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Prohibited Transaction Issues

Section 406 of ERISA and Section 4975 of the Code prohibit ERISA Plans from engaging in specified transactions involving plan assets with persons or entities who are "parties in interest," within the meaning of ERISA, or "disqualified persons," within the meaning of Section 4975 of the Code, unless an exemption is available. A party in interest or disqualified person who engages in a non-exempt prohibited transaction may be subject to excise taxes and other penalties and liabilities under ERISA and the Code. In addition, the fiduciary of the ERISA Plan that engages in such a non-exempt prohibited transaction may be subject to excise taxes, penalties and liabilities under ERISA and the Code. The acquisition and/or holding of shares of common stock by an ERISA Plan with respect to which the issuer, the underwriter, or a guarantor is considered a party in interest or a disqualified person may constitute or result in a direct or indirect prohibited transaction under Section 406 of ERISA and/or Section 4975 of the Code, unless the investment is acquired and is held in accordance with an applicable statutory, class or individual prohibited transaction exemption.

Because of the foregoing, shares of common stock should not be acquired or held by any person investing "plan assets" of any Plan, unless such acquisition and holding will not constitute a non-exempt prohibited transaction under ERISA and the Code or a similar violation of any applicable Similar Laws.

Plan Asset Issues

Additionally, a fiduciary of a Plan should consider whether the Plan will, by investing in us, be deemed to own an undivided interest in our assets, with the result that we would become a fiduciary of the Plan and our operations would be subject to the regulatory restrictions of ERISA, including its prohibited transaction rules, as well as the prohibited transaction rules of the Code and any other applicable Similar Laws.

The Department of Labor (the "DOL") regulations provide guidance with respect to whether the assets of an entity in which ERISA Plans acquire equity interests would be deemed "plan assets" under some circumstances. Under these regulations, an entity's assets generally would not be considered to be "plan assets" if, among other things:

The foregoing discussion of issues arising for investments by employee benefit plans under ERISA, the Code and applicable Similar Laws is general in nature and is not intended to be all inclusive and is based on laws in effect on the date of this prospectus supplement. This discussion should not be construed as legal advice. Due to the

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complexity of these rules and the excise taxes, penalties and liabilities that may be imposed upon persons involved in non-exempt prohibited transactions, it is particularly important that fiduciaries, or other persons considering acquiring and/or holding shares of our common stock on behalf of, or with the assets of, any Plan, consult with their counsel regarding the potential applicability of ERISA, Section 4975 of the Code and any Similar Laws to such investment and whether an exemption would be applicable to the acquisition and holding of shares of common stock. Purchasers of shares of common stock have the exclusive responsibility for ensuring that their acquisition and holding of shares of common stock complies with the fiduciary responsibility rules of ERISA and does not violate the prohibited transaction rules of ERISA, the Code or applicable Similar Laws. The sale of shares of common stock to a Plan is in no respect a representation by us or any of our affiliates or representatives that such an investment meets all relevant legal requirements with respect to investments by any such Plan or that such investment is appropriate for any such Plan.

MATERIAL U.S. FEDERAL INCOME TAX CONSIDERATIONS FOR NON-U.S. HOLDERS

The following is a summary of the material U.S. federal income tax considerations related to the purchase, ownership and disposition of our Class A common stock by a non-U.S. holder (as defined below) that holds our Class A common stock as a "capital asset" within the meaning of Section 1221 of the Internal Revenue Code of 1986, as amended (the "Code") (generally, property held for investment). This summary is based on the provisions of the Code, U.S. Treasury regulations promulgated thereunder, administrative rulings and judicial decisions, all as in effect on the date hereof, and all of which are subject to change or differing interpretations, possibly with retroactive effect. We cannot assure you that a change in law will not significantly alter the tax considerations that we describe in this summary. We have not sought any ruling from the Internal Revenue Service ("IRS") with respect to the statements made and the positions and conclusions described in the following summary, and there can be no assurance that the IRS or a court will agree with such statements, positions, and conclusions.

This summary does not address all aspects of U.S. federal income taxation that may be relevant to non-U.S. holders in light of their personal circumstances. In addition, this summary does not address the impact of the Medicare surtax on certain net investment income, U.S. federal estate or gift tax laws, any U.S. state or local or non-U.S. tax laws or any tax treaties. This summary also does not address all U.S. federal income tax considerations that may be relevant to particular non-U.S. holders in light of their personal circumstances or that may be relevant to certain categories of investors that may be subject to special rules, such as:

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PROSPECTIVE INVESTORS SHOULD CONSULT WITH THEIR OWN TAX ADVISORS WITH RESPECT TO THE APPLICATION OF THE U.S. FEDERAL INCOME TAX LAWS (INCLUDING ANY POTENTIAL FUTURE CHANGES THERETO) TO THEIR PARTICULAR SITUATION, AS WELL AS ANY TAX CONSEQUENCES OF THE PURCHASE, OWNERSHIP AND DISPOSITION OF OUR CLASS A COMMON STOCK ARISING UNDER ANY OTHER TAX LAWS, INCLUDING U.S. FEDERAL ESTATE OR GIFT TAX LAWS OR UNDER THE LAWS OF ANY U.S. STATE OR LOCAL OR NON-U.S. TAXING JURISDICTION, OR UNDER ANY APPLICABLE INCOME TAX TREATY.

Non-U.S. Holder Defined

For purposes of this discussion, a "non-U.S. holder" is a beneficial owner of our Class A common stock that is not for U.S. federal income tax purposes a partnership or any of the following:

If an entity or arrangement treated as a partnership for U.S. federal income tax purposes holds our Class A common stock, the tax treatment of a partner in such partnership generally will depend upon the status of the partner, the activities of such partnership and certain determinations made at the partner level. Accordingly, we urge partners in entities or arrangements treated as partnerships for U.S. federal income tax purposes considering the purchase of our Class A common stock to consult with their own tax advisors regarding the U.S. federal income tax considerations of the purchase, ownership and disposition of our Class A common stock by such partnership.

Distributions

Distributions of cash or other property on our Class A common stock, if any, will constitute dividends for U.S. federal income tax purposes to the extent paid from our current or accumulated earnings and profits, as determined under U.S. federal income tax principles. To the extent those distributions exceed our current and accumulated earnings and profits, the distributions will be treated as a non-taxable return of capital to the extent of the non-U.S. holder's tax basis in our Class A common stock and thereafter as capital gain from the sale or exchange of such Class A common stock. See "-Gain on Sale or Other Taxable Disposition of Class A Common Stock." Subject to the withholding requirements under FATCA (as defined below) and with respect to effectively connected dividends, each of which is discussed below, any distribution made to a non-U.S. holder on our Class A common stock generally will be subject to U.S. withholding tax at a rate of 30% of the gross amount

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of the distribution unless an applicable income tax treaty provides for a lower rate. To receive the benefit of a reduced treaty rate, a non-U.S. holder must provide the applicable withholding agent with an IRS Form W-8BEN or IRS Form W-8BEN-E (or other applicable or successor form) certifying qualification for the reduced rate.

Dividends paid to a non-U.S. holder that are effectively connected with a trade or business conducted by the non-U.S. holder in the United States (and, if required by an applicable income tax treaty, are treated as attributable to a permanent establishment maintained by the non-U.S. holder in the United States) generally will be taxed on a net income basis at the rates and in the manner generally applicable to United States persons. Such effectively connected dividends will not be subject to U.S. withholding tax if the non-U.S. holder satisfies certain certification requirements by providing the applicable withholding agent with a properly executed IRS Form W-8ECI certifying eligibility for exemption. If the non-U.S. holder is a corporation for U.S. federal income tax purposes, it may also be subject to a branch profits tax (at a 30% rate or such lower rate as specified by an applicable income tax treaty) on its effectively connected earnings and profits (as adjusted for certain items), which will include effectively connected dividends.

Gain on Sale or Other Taxable Disposition of Class A Common Stock

Subject to the discussion below under "-Backup Withholding and Information Reporting," a non-U.S. holder generally will not be subject to U.S. federal income or withholding tax on any gain realized upon the sale or other taxable disposition of our Class A common stock unless:

A non-U.S. holder described in the first bullet point above will be subject to U.S. federal income tax at a rate of 30% (or such lower rate as specified by an applicable income tax treaty) on the amount of such gain, which generally may be offset by U.S. source capital losses provided the non-U.S. holder has timely filed U.S. federal income tax returns with respect to such losses.

A non-U.S. holder whose gain is described in the second bullet point above or, subject to the exceptions described in the next paragraph, the third bullet point above, generally will be taxed on a net income basis at the rates and in the manner generally applicable to United States persons. If the non-U.S. holder is a corporation for U.S. federal income tax purposes whose gain is described in the second bullet point above, then such gain would also be included in its effectively connected earnings and profits (as adjusted for certain items), which may be subject to a branch profits tax (at a 30% rate or such lower rate as specified by an applicable income tax treaty).

Generally, a corporation is a USRPHC if the fair market value of its United States real property interests equals or exceeds 50% of the sum of the fair market value of its worldwide real property interests and its other assets used or held for use in a trade or business. We believe that we currently are not a USRPHC for U.S. federal income tax purposes, and we do not expect to become a USRPHC for the foreseeable future. However, in the event that we were to become a USRPHC, as long as our Class A common stock continues to be "regularly traded on an established securities market" (within the meaning of the U.S. Treasury regulations), only a

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non-U.S. holder that actually or constructively owns, or owned at any time during the shorter of the five-year period ending on the date of the disposition or the non-U.S. holder's holding period for the Class A common stock, more than 5% of our Class A common stock will be treated as disposing of a United States real property interest and will be taxable on gain realized on the disposition of our Class A common stock as a result of our status as a USRPHC. If we were to become a USRPHC and our Class A common stock were not considered to be regularly traded on an established securities market, each non-U.S. holder (regardless of the percentage of stock owned) would be treated as disposing of a United States real property interest and would be subject to U.S. federal income tax on a taxable disposition of our Class A common stock (as described in the preceding paragraph), and a 15% withholding tax would apply to the gross proceeds from such disposition.

Non-U.S. holders should consult with their own tax advisors with respect to the application of the foregoing rules to their ownership and disposition of our Class A common stock, including regarding potentially applicable income tax treaties that may provide for different rules.

Backup Withholding and Information Reporting

Any distributions paid to a non-U.S. holder must be reported annually to the IRS and to the non-U.S. holder. Copies of these information returns may be made available to the tax authorities in the country in which the non-U.S. holder resides or is established. Payments of dividends to a non-U.S. holder generally will not be subject to backup withholding if the non-U.S. holder establishes an exemption by properly certifying its non-U.S. status on an IRS Form W-8BEN or IRS Form W-8BEN-E (or other applicable or successor form).

Payments of the proceeds from a sale or other disposition by a non-U.S. holder of our Class A common stock effected by or through a U.S. office of a broker generally will be subject to information reporting and backup withholding (at the applicable rate) unless the non-U.S. holder establishes an exemption by properly certifying its non-U.S. status on an IRS Form W-8BEN or IRS Form W-8BEN-E (or other applicable or successor form) and certain other conditions are met. Information reporting and backup withholding generally will not apply to any payment of the proceeds from a sale or other disposition of our Class A common stock effected outside the United States by a non-U.S. office of a broker. However, unless such broker has documentary evidence in its records that the non-U.S. holder is not a United States person and certain other conditions are met, or the non-U.S. holder otherwise establishes an exemption, information reporting will apply to a payment of the proceeds of the disposition of our Class A common stock effected outside the United States by such a broker if it has certain relationships within the United States.

Backup withholding is not an additional tax. Rather, the U.S. federal income tax liability (if any) of persons subject to backup withholding will be reduced by the amount of tax withheld. If backup withholding results in an overpayment of taxes, a refund may be obtained, provided that the required information is timely furnished to the IRS.

Additional Withholding Requirements under FATCA

Sections 1471 through 1474 of the Code, and the U.S. Treasury regulations and administrative guidance issued thereunder ("FATCA"), impose a 30% withholding tax on "withholdable payments" (as defined in the Code), including dividends on our Class A common stock, if paid to a "foreign financial institution" or a "non-financial foreign entity" (each as defined in the Code) (including, in some cases, when such foreign financial institution or non-financial foreign entity is acting as an intermediary), unless (i) in the case of a foreign financial institution, such institution enters into an agreement with the U.S. government to withhold on certain payments and to collect and provide to the U.S. tax authorities substantial information regarding U.S. account holders of such institution (which includes certain equity and debt holders of such institution, as well as certain account holders that are non-U.S. entities with U.S. owners), (ii) in the case of a non-financial foreign entity,

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such entity certifies that it does not have any "substantial United States owners" (as defined in the Code) or provides the applicable withholding agent with a certification identifying the direct and indirect substantial United States owners of the entity (in either case, generally on an IRS Form W-8BEN-E), or (iii) the foreign financial institution or non-financial foreign entity otherwise qualifies for an exemption from these rules and provides appropriate documentation (such as an IRS Form W-8BEN-E). Foreign financial institutions located in jurisdictions that have an intergovernmental agreement with the United States governing these rules may be subject to different rules. Under certain circumstances, a holder might be eligible for refunds or credits of such taxes. While gross proceeds from a sale or other disposition of our Class A common stock would have originally been subject to withholding under FATCA, proposed U.S. Treasury regulations provide that such payments of gross proceeds do not constitute withholdable payments. Taxpayers may generally rely on these proposed U.S. Treasury regulations until they are revoked or final U.S. Treasury regulations are issued. Non-U.S. holders are encouraged to consult with their own tax advisors regarding the effects of FATCA on an investment in our Class A common stock.

INVESTORS CONSIDERING THE PURCHASE OF OUR CLASS A COMMON STOCK SHOULD CONSULT WITH THEIR OWN TAX ADVISORS REGARDING THE APPLICATION OF THE U.S. FEDERAL INCOME TAX LAWS (INCLUDING ANY POTENTIAL FUTURE CHANGES THERETO) TO THEIR PARTICULAR SITUATIONS AND THE APPLICABILITY AND EFFECT OF ANY OTHER TAX LAWS, INCLUDING U.S. FEDERAL ESTATE AND GIFT TAX LAWS AND ANY U.S. STATE OR LOCAL OR NON-U.S. TAX LAWS, AND TAX TREATIES.

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UNDERWRITING

Under the terms and subject to the conditions in an underwriting agreement dated the date of this prospectus supplement, the Underwriter for this offering, Morgan Stanley & Co. LLC, on behalf of itself and/or its affiliates will facilitate the hedging transactions by the Convertible Arbitrage Investors subscribing for our Notes as described in this prospectus supplement.

The number of shares of Class A common stock subject to this offering will depend on what portion of Convertible Arbitrage Investors desire to hedge their investment in the Notes offered in the Concurrent Notes Offering and is expected to be no greater than commercially reasonable initial short positions of the Convertible Arbitrage Investors being established to facilitate their market risk hedging with respect to the Notes they acquire. We have been advised that the shares of Class A common stock sold by the Underwriter in this offering will be borrowed from non-affiliate third parties, and will be: (x) purchased by the Underwriter from certain Convertible Arbitrage Investors who have sold them short to such Underwriter in connection with the Concurrent Notes Offering and who may be deemed statutory underwriters under the Securities Act with respect to the offering of such shares of Class A common stock under this prospectus supplement and/or (y) sold short by the Underwriter to facilitate concurrent privately negotiated transactions between the Underwriter (or its affiliates) with certain Convertible Arbitrage Investors seeking a short exposure to shares of our Class A common stock through a derivative, in an equivalent notional amount, in each case, with a view for the Underwriter to initially offer the shares of our Class A common stock to the public at a price of $    per share of our Class A common stock and to subsequently offer the shares of our Class A common stock for sale in one or more transactions on the New York Stock Exchange, in the over-the-counter market, through negotiated transactions or otherwise, at market prices prevailing at the time of sale, at prices related to prevailing market prices at the time of sale, at prices related to prevailing market prices or at negotiated prices.

There can be no assurance that the Underwriter will sell any or all of the shares of our Class A common stock offered pursuant to this prospectus supplement, or the timing of any such sales.

We will pay to the Underwriter a fee of $    per share for the shares of Class A common stock sold by the Underwriter in this offering. We have also agreed to reimburse the Underwriter for certain of their expenses in an amount up to: $    .

We have agreed to indemnify the Underwriter against certain liabilities, including liabilities arising under the Securities Act.

The Underwriter and certain of its affiliates are full service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, investment research, principal investment, hedging, financing and brokerage activities. The Underwriter is serving as an underwriter in the Concurrent Notes Offering. The Underwriter and certain of its affiliates may in the future engage in investment banking and other commercial dealings in the ordinary course of business with us and our affiliates, for which they may in the future receive customary fees, commissions and expenses. Furthermore, concurrently with this offering, the Underwriter or its affiliates is expected to facilitate privately negotiated transactions with certain Convertible Arbitrage Investors seeking a short exposure to shares of our Class A common stock through a derivative, to facilitate such Convertible Arbitrage Investors' hedging of their market price with respect to the Notes, which transactions are expected to be on customary market terms.

In addition, in the ordinary course of their business activities, the Underwriter and its affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers. Such investments and securities activities may involve securities and/or instruments of ours or our affiliates. The Underwriter and its affiliates may also make investment recommendations and/or publish or express independent

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research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

We, the Underwriter or other agents may engage in derivative transactions involving the securities. These derivatives may consist of short sale transactions and other hedging activities. The Underwriter or agents may acquire long or short positions in the securities, hold or resell securities acquired and purchase options or futures on the securities and other derivative instruments with returns linked to or related to changes in the price of the securities. In order to facilitate these derivative transactions, we may enter into security lending or repurchase agreements with the Underwriter or agents. The Underwriter or agents may effect the derivative transactions through sales of the securities to the public, including short sales, or by lending the securities in order to facilitate short sale transactions by others. The Underwriter or agents may also use the securities purchased or borrowed from us or others (or, in the case of derivatives, also securities received from us in settlement of those derivatives) to directly or indirectly settle sales of the securities or close out any related open borrowings of the securities.

See "Plan of Distribution" on page 9 of the accompanying base prospectus for more information

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SELLING RESTRICTIONS

EEA Restriction

In relation to each Member State of the European Economic Area which has implemented the Prospectus Directive (each, a "Relevant Member State") an offer to the public of any shares which are the subject of the offering contemplated by this prospectus (the "Shares") may not be made in that Relevant Member State except that an offer to the public in that Relevant Member State of any Shares may be made at any time under the following exemptions under the Prospectus Directive, if they have been implemented in that Relevant Member State:

provided that no such offer of Shares shall result in a requirement for the Company or any underwriter to publish a prospectus pursuant to Article 3 of the Prospectus Directive or supplement a prospectus pursuant to Article 16 of the Prospectus Directive.

For the purposes of this provision, the expression an "offer to the public" in relation to any Shares in any Relevant Member State means the communication in any form and by any means of sufficient information on the terms of the offer and any Shares to be offered so as to enable an investor to decide to purchase any Shares, as the same may be varied in that Member State by any measure implementing the Prospectus Directive in that Member State, the expression "Prospectus Directive" means Directive 2003/71/EC (and amendments thereto, including the 2010 PD Amending Directive, to the extent implemented in the Relevant Member State), and includes any relevant implementing measure in each Relevant Member State and the expression "2010 PD Amending Directive" means Directive 2010/73/EU.

United Kingdom

Each underwriter has represented and agreed that:

Notice to United Kingdom Investors

This prospectus is only being distributed to and is only directed at (i) persons who are outside the United Kingdom or (ii) investment professionals falling within Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005 (the "Order") or (iii) high net worth companies, and other persons to whom it may lawfully be communicated, falling within Article 49(2)(a) to (d) of the Order (all such persons together being referred to as "relevant persons"). The Shares are only available to, and any invitation, offer or agreement to subscribe, purchase or otherwise acquire such Shares will be engaged in only with, relevant persons. Any person who is not a relevant person should not act or rely on this document or any of its contents.

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Hong Kong

The shares may not be offered or sold by means of any document other than (i) in circumstances which do not constitute an offer to the public within the meaning of the Companies Ordinance (Cap. 32, Laws of Hong Kong), or (ii) to "professional investors" within the meaning of the Securities and Futures Ordinance (Cap. 571, Laws of Hong Kong) and any rules made thereunder, or (iii) in other circumstances which do not result in the document being a "prospectus" within the meaning of the Companies Ordinance (Cap. 32, Laws of Hong Kong), and no advertisement, invitation or document relating to the shares may be issued or may be in the possession of any person for the purpose of issue (in each case whether in Hong Kong or elsewhere), which is directed at, or the contents of which are likely to be accessed or read by, the public in Hong Kong (except if permitted to do so under the laws of Hong Kong) other than with respect to shares which are or are intended to be disposed of only to persons outside Hong Kong or only to "professional investors" within the meaning of the Securities and Futures Ordinance (Cap. 571, Laws of Hong Kong) and any rules made thereunder.

Singapore

This prospectus has not been registered as a prospectus with the Monetary Authority of Singapore. Accordingly, this prospectus and any other document or material in connection with the offer or sale, or invitation for subscription or purchase, of the shares may not be circulated or distributed, nor may the shares be offered or sold, or be made the subject of an invitation for subscription or purchase, whether directly or indirectly, to persons in Singapore other than (i) to an institutional investor under Section 274 of the Securities and Futures Act, Chapter 289 of Singapore, or the SFA, (ii) to a relevant person, or any person pursuant to Section 275(1A), and in accordance with the conditions, specified in Section 275 of the SFA or (iii) otherwise pursuant to, and in accordance with the conditions of, any other applicable provision of the SFA.

Where the shares are subscribed or purchased under Section 275 by a relevant person which is: (a) a corporation (which is not an accredited investor) the sole business of which is to hold investments and the entire share capital of which is owned by one or more individuals, each of whom is an accredited investor; or (b) a trust (where the trustee is not an accredited investor) whose sole purpose is to hold investments and each beneficiary is an accredited investor, shares, debentures and units of shares and debentures of that corporation or the beneficiaries' rights and interest in that trust shall not be transferable for 6 months after that corporation or that trust has acquired the shares under Section 275 except: (1) to an institutional investor under Section 274 of the SFA or to a relevant person, or any person pursuant to Section 275(1A), and in accordance with the conditions, specified in Section 275 of the SFA; (2) where no consideration is given for the transfer; or (3) by operation of law.

Japan

The securities have not been and will not be registered under the Financial Instruments and Exchange Law of Japan, or the Financial Instruments and Exchange Law, and each underwriter has agreed that it will not offer or sell any securities, directly or indirectly, in Japan or to, or for the benefit of, any resident of Japan (which term as used herein means any person resident in Japan, including any corporation or other entity organized under the laws of Japan), or to others for re-offering or resale, directly or indirectly, in Japan or to a resident of Japan, except pursuant to an exemption from the registration requirements of, and otherwise in compliance with, the Financial Instruments and Exchange Law and any other applicable laws, regulations and ministerial guidelines of Japan.

Notice to Canadian Residents

Resale Restrictions

The distribution of our Class A common stock in Canada is being made only in the provinces of Ontario, Quebec, Alberta and British Columbia on a private placement basis exempt from the requirement that we prepare

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and file a prospectus with the securities regulatory authorities in each province where trades of these securities are made. Any resale of our Class A common stock in Canada must be made under applicable Canadian securities laws which may vary depending on the relevant jurisdiction, and which may require resales to be made under available statutory exemptions or under a discretionary exemption granted by the applicable Canadian securities regulatory authority. These resale restrictions may under certain circumstances apply to resales outside of Canada. Purchasers are advised to seek legal advice prior to any resale of the securities.

Representations of Canadian Purchasers

By purchasing our Class A common stock in Canada and accepting delivery of a purchase confirmation, a purchaser is representing to us and the dealer from whom the purchase confirmation is received that:

Conflicts of Interest

Canadian purchasers are hereby notified that the underwriters are relying on the exemption set out in section 3A.3 or 3A.4, if applicable, of National Instrument 33-105 Underwriting Conflicts from having to provide certain underwriter conflicts of interest disclosure in connection with this offering.

Statutory Rights of Action

Securities legislation in certain provinces or territories of Canada may provide a purchaser with remedies for rescission or damages if the prospectus (including any amendment thereto) such as this document contains a misrepresentation, provided that the remedies for rescission or damages are exercised by the purchaser within the time limit prescribed by the securities legislation of the purchaser's province or territory. The purchaser of these securities in Canada should refer to any applicable provisions of the securities legislation of the purchaser's province or territory for particulars of these rights or consult with a legal advisor.

Enforcement of Legal Rights

All of our directors and officers as well as the experts named herein may be located outside of Canada and, as a result, it may not be possible for Canadian purchasers to effect service of process within Canada upon us or those persons. All or a substantial portion of our assets and the assets of those persons may be located outside of Canada and, as a result, it may not be possible to satisfy a judgment against us or those persons in Canada or to enforce a judgment obtained in Canadian courts against us or those persons outside of Canada.

Taxation and Eligibility for Investment

Canadian purchasers of our Class A common stock should consult their own legal and tax advisors with respect to the tax consequences of an investment in our Class A common stock in their particular circumstances and about the eligibility of our Class A common stock for investment by the purchaser under relevant Canadian legislation.

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Language of Documents

Each Canadian purchaser hereby confirms its express wish that all documents evidencing or relating in any way to the sale of securities described herein and all other contracts and related documents be drafted in the English language. Chaque investisseur Canadian confirme sa volonté expresse que tous les documents faisant foi ou se rapportant de quelque manière que ce soit à la vente des valeurs mobilières décrites aux présentes ainsi que tous les autres contrats et documents s'y rattachant soient rédigées en langue anglaise.

Australia

This prospectus supplement:

The shares of common stock may not be directly or indirectly offered for subscription or purchased or sold, and no invitations to subscribe for or buy the shares of common stock may be issued, and no draft or definitive prospectus, advertisement or other offering material relating to any shares of common stock may be distributed in Australia, except where disclosure to investors is not required under Chapter 6D of the Corporations Act or is otherwise in compliance with all applicable Australian laws and regulations. By submitting an application for the shares of common stock, you represent and warrant to us that you are an Exempt Investor. As any offer of shares of common stock under this document will be made without disclosure in Australia under Chapter 6D.2 of the Corporations Act, the offer of those securities for resale in Australia within 12 months may, under section 707 of the Corporations Act, require disclosure to investors under Chapter 6D.2 if none of the exemptions in section 708 applies to that resale. By applying for the shares of common stock you undertake to us that you will not, for a period of 12 months from the date of issue of the shares of common stock, offer, transfer, assign or otherwise alienate those shares of common stock to investors in Australia except in circumstances where disclosure to investors is not required under Chapter 6D.2 of the Corporations Act or where a compliant disclosure document is prepared and lodged with ASIC.

Dubai International Financial Centre (DIFC)

This document relates to an Exempt Offer in accordance with the Markets Rules 2012 of the Dubai Financial Services Authority, or DFSA. This document is intended for distribution only to persons of a type specified in the Markets Rules 2012 of the DFSA. It must not be delivered to, or relied on by, any other person. The DFSA has no responsibility for reviewing or verifying any documents in connection with Exempt Offers. The DFSA has not approved this prospectus supplement nor taken steps to verify the information set forth herein and has no responsibility for this document. The securities to which this document relates may be illiquid and/or subject to restrictions on their resale. Prospective purchasers of the securities offered should conduct their own due diligence on the securities. If you do not understand the contents of this document, you should consult an authorized financial advisor. In relation to its use in the DIFC, this document is strictly private and confidential and is being distributed to a limited number of investors and must not be provided to any person other than the original recipient, and may not be reproduced or used for any other purpose. The interests in the securities may not be offered or sold directly or indirectly to the public in the DIFC.

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Switzerland

The shares of common stock may not be publicly offered in Switzerland and will not be listed on the SIX Swiss Exchange, or SIX, or on any other stock exchange or regulated trading facility in Switzerland. This document does not constitute a prospectus within the meaning of, and has been prepared without regard to the disclosure standards for issuance prospectuses under art. 652a or art. 1156 of the Swiss Code of Obligations or the disclosure standards for listing prospectuses under art. 27 ff. of the SIX Listing Rules or the listing rules of any other stock exchange or regulated trading facility in Switzerland. Neither this document nor any other offering or marketing material relating to the shares of common stock or the offering may be publicly distributed or otherwise made publicly available in Switzerland.

Neither this document nor any other offering or marketing material relating to the offering, us, the shares of common stock have been or will be filed with or approved by any Swiss regulatory authority. In particular, this document will not be filed with, and the offer of shares of common stock will not be supervised by, the Swiss Financial Market Supervisory Authority FINMA, or FINMA, and the offer of shares of common stock has not been and will not be authorized under the Swiss Federal Act on Collective Investment Schemes, or CISA. The investor protection afforded to acquirers of interests in collective investment schemes under the CISA does not extend to acquirers of shares of common stock.

Israel

In the State of Israel this prospectus supplement shall not be regarded as an offer to the public to purchase shares of common stock under the Israeli Securities Law, 5728-1968, which requires a prospectus to be published and authorized by the Israel Securities Authority, if it complies with certain provisions of Section 15 of the Israeli Securities Law, 5728-1968, including, inter alia, if: (i) the offer is made, distributed or directed to not more than 35 investors, subject to certain conditions, or the Addressed Investors; or (ii) the offer is made, distributed or directed to certain qualified investors defined in the First Addendum of the Israeli Securities Law, 5728-1968, subject to certain conditions, or the "Qualified Investors". The Qualified Investors shall not be taken into account in the count of the Addressed Investors and may be offered to purchase securities in addition to the 35 Addressed Investors. We have not and will not take any action that would require it to publish a prospectus in accordance with and subject to the Israeli Securities Law, 5728-1968. We have not and will not distribute this prospectus supplement or make, distribute or direct an offer to subscribe for our shares of common stock to any person within the State of Israel, other than to Qualified Investors and up to 35 Addressed Investors. Qualified Investors may have to submit written evidence that they meet the definitions set out in of the First Addendum to the Israeli Securities Law, 5728-1968. In particular, we may request, as a condition to be offered shares of common stock, that Qualified Investors will each represent, warrant and certify to us and/or to anyone acting on our behalf: (i) that it is an investor falling within one of the categories listed in the First Addendum to the Israeli Securities Law, 5728-1968; (ii) which of the categories listed in the First Addendum to the Israeli Securities Law, 5728-1968 regarding Qualified Investors is applicable to it; (iii) that it will abide by all provisions set forth in the Israeli Securities Law, 5728-1968 and the regulations promulgated thereunder in connection with the offer to be issued shares of common stock; (iv) that the shares of common stock that it will be issued are, subject to exemptions available under the Israeli Securities Law, 5728-1968: (a) for its own account; (b) for investment purposes only; and (c) not issued with a view to resale within the State of Israel, other than in accordance with the provisions of the Israeli Securities Law, 5728-1968; and (v) that it is willing to provide further evidence of its Qualified Investor status. Addressed Investors may have to submit written evidence in respect of their identity and may have to sign and submit a declaration containing, inter alia, the Addressed Investor's name, address and passport number or Israeli identification number.

United Arab Emirates

The shares of common stock have not been, and are not being, publicly offered, sold, promoted or advertised in the United Arab Emirates (including the Abu Dhabi Global Market and the Dubai International Financial Centre)

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other than in compliance with the laws, regulations and rules of the United Arab Emirates, the Abu Dhabi Global Market and the Dubai International Financial Centre governing the issue, offering and sale of securities. Further, this prospectus supplement, the accompanying prospectus and any other offering or marketing material relating to the shares of common stock or the offering do not constitute a public offer of securities in the United Arab Emirates (including the Abu Dhabi Global Market and the Dubai International Financial Centre) and are not intended to be a public offer. This prospectus supplement, the accompanying prospectus and any other offering or marketing material relating to the shares of common stock or the offering have not been approved by or filed with the Central Bank of the United Arab Emirates, the Securities and Commodities Authority, the Financial Services Regulatory Authority, the Dubai Financial Services Authority or any other relevant licensing authorities in the United Arab Emirates.

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LEGAL MATTERS

The validity of our Class A common stock offered by this prospectus will be passed upon for us by Vinson & Elkins L.L.P., Houston, Texas. Certain legal matters in connection with this offering will be passed upon for the Underwriter by Latham & Watkins LLP, Houston, Texas.

EXPERTS

The consolidated financial statements of Solaris Energy Infrastructure, Inc. as of December 31, 2024 and 2023 and for each of the years then ended and management's assessment of the effectiveness of internal control over financial reporting as of December 31, 2024, incorporated by reference in this prospectus supplement, have been so incorporated in reliance on the reports of BDO USA, P.C., an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting. The report on the effectiveness of internal control over financial reporting contains an explanatory paragraph relating to the exclusion of Mobile Energy Rentals, LLC from the scope of management's assessment of the effectiveness of internal control over financial reporting and our audit of internal control over financial reporting as of December 31, 2024.

The financial statements of Mobile Energy Rentals, LLC as of December 31, 2023 and 2022, and for the year ended December 31, 2023 and the period from February 23, 2022 (inception) to December 31, 2022, incorporated by reference in this prospectus supplement, have been so incorporated in reliance on the report of BDO USA, P.C., independent auditors, given on the authority of said firm as experts in auditing and accounting. The report on the financial statements contains an explanatory paragraph regarding Mobile Energy Rentals, LLC's ability to continue as a going concern.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement on Form S-3 (including the exhibits, schedules and amendments thereto) under the Securities Act, with respect to the shares of our Class A common stock offered hereby. This prospectus supplement does not contain all of the information set forth in the registration statement and the exhibits and schedules thereto. For further information with respect to us and the Class A common stock offered hereby, we refer you to the registration statement and the exhibits and schedules filed therewith and the accompanying base prospectus. Statements contained in this prospectus supplement as to the contents of any contract, agreement or any other document are summaries of the material terms of this contract, agreement or other document. With respect to each of these contracts, agreements or other documents filed as an exhibit to the registration statement, reference is made to the exhibits for a more complete description of the matter involved.

The SEC maintains a website at www.sec.gov that contains reports, proxy and information statements and other information regarding registrants that file electronically with the SEC. Our registration statement, of which this prospectus supplement constitutes a part, can be downloaded from the SEC's website. We file with or furnish to the SEC periodic reports and other information. These reports and other information may be obtained from the SEC's website as provided above. Our website is located at www.solaris-energy.com. We make our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K, amendments to those reports and other information filed with or furnished to the SEC available, free of charge, through our website, as soon as reasonably practicable after those reports and other information are electronically filed with or furnished to the SEC. We make our website content available for information purposes only. Information on our website or any other website is not incorporated by reference into this prospectus supplement and does not constitute a part of this prospectus supplement and investors should not rely on such information in making a decision to purchase our Class A common stock.

We furnish or make available to our stockholders annual reports containing our audited financial statements prepared in accordance with GAAP. We also furnish or make available to our stockholders quarterly reports containing our unaudited interim financial information, including the information required by Form 10-Q, for the first three fiscal quarters of each fiscal year.

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INCORPORATION OF CERTAIN INFORMATION BY REFERENCE

We "incorporate by reference" into this prospectus documents we file with the SEC, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is an important part of this prospectus. Some information contained in this prospectus updates the information incorporated by reference, and information that we file subsequently with the SEC will automatically update this prospectus. In other words, in the case of a conflict or inconsistency between information set forth in this prospectus and information that we file later and incorporate by reference into this prospectus, you should rely on the information contained in the document that was filed later.

In particular, we incorporate by reference into this prospectus supplement the documents listed below and any filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act (other than, in each case, documents or information deemed to have been "furnished" and not "filed" in accordance with SEC rules):

Any statement contained in a document incorporated or deemed to be incorporated by reference in this prospectus will be deemed to be modified or superseded to the extent that a statement contained herein or in any other subsequently filed document which also is or is deemed to be incorporated by reference in this prospectus modifies or supersedes that statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus.

You may request a copy of the registration statement, the above filings and any future filings that are incorporated by reference into this prospectus, other than an exhibit to a filing unless that exhibit is specifically incorporated by reference into that filing, at no cost, by writing or calling us at the following address:

Solaris Energy Infrastructure, Inc.

Attention: Investor Relations

9651 Katy Freeway, Suite 300

Houston, Texas 77024

(281) 501-3070

S-31

PROSPECTUS

Solaris Energy Infrastructure, Inc.

Class A Common Stock

Preferred Stock

Debt Securities

From time to time we may offer and sell the following securities:

We may offer and sell these securities from time to time in amounts, at prices and on terms to be determined by market conditions and other factors at the time of our offerings. We may offer and sell these securities through agents, through underwriters or dealers or directly to one or more purchasers, including existing stockholders. This prospectus provides you with a general description of these securities and the general manner in which we will offer the securities. Each time securities are offered, we will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement may also add, update or change information contained in this prospectus.

We are also registering hereunder an indeterminate number of shares of our Class A common stock to the extent necessary upon conversion of any debt securities sold hereunder.

Our Class A common stock is traded on the New York Stock Exchange under the symbol "SEI."

You should read carefully this prospectus, the documents incorporated by reference in this prospectus and any prospectus supplement before you invest. See "Risk Factors" beginning on page 2 of this prospectus for information on certain risks related to the purchase of our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is October 6, 2025.

TABLE OF CONTENTS

You should rely only on the information contained in this prospectus, any prospectus supplement and the documents we have incorporated by reference herein. We have not authorized any dealer, salesperson or other person to provide you with additional or different information. If anyone provides you with different or inconsistent information, you should not rely on it. This prospectus and any prospectus supplement are not an offer to sell or the solicitation of an offer to buy any securities other than the securities to which they relate and are not an offer to sell or the solicitation of an offer to buy securities in any jurisdiction to any person to whom it is unlawful to make an offer or solicitation in that jurisdiction. You should not assume that the information contained in this prospectus is accurate as of any date other than the date on the front cover of this prospectus, or that the information contained in any document incorporated by reference is accurate as of any date other than the date of the document incorporated by reference, regardless of the time of delivery of this prospectus or any sale of a security. Our business, financial condition, results of operation and prospects may have changed since that date.

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ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we have filed with the U.S. Securities and Exchange Commission (the "SEC") using a "shelf" registration process. Under this shelf registration process, we may, from time to time, offer and sell any combination of the securities described in this prospectus in one or more offerings. This prospectus generally describes Solaris Energy Infrastructure, Inc. and the securities we may offer. Each time securities are offered by means of this prospectus, we will provide a prospectus supplement that will contain specific information about the terms of that offering. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings. We may also add or update in the prospectus supplement (and in any related free writing prospectus that we may authorize to be provided to you) any of the information contained in this prospectus or in the documents that we have incorporated by reference into this prospectus. Please read this prospectus, any applicable prospectus supplement and any related free writing prospectus, together with the information incorporated herein by reference as described under the heading "Where You Can Find More Information," carefully before buying any of the securities being offered.

This prospectus contains summaries of certain provisions contained in some of the documents described herein, but reference is made to the actual documents for complete information. All of the summaries are qualified in their entirety by the actual documents. Copies of some of the documents referred to herein have been filed, will be filed or are incorporated by reference as exhibits to the registration statement of which this prospectus is a part, and you may obtain copies of those documents as described below under the heading "Where You Can Find More Information."

Unless context otherwise requires, references in this prospectus to the "Company," "we," "our," "us" or like terms refer to Solaris Energy Infrastructure, Inc. and its subsidiaries and predecessors.

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WHERE YOU CAN FIND MORE INFORMATION

We have filed a registration statement with the SEC under the Securities Act of 1933, as amended (the "Securities Act"), that registers the offer and sale of the securities covered by this prospectus. The registration statement, including the exhibits attached thereto and incorporated by reference therein, contains additional relevant information about us. In addition, we file annual, quarterly and other reports and other information with the SEC. The SEC maintains a website that contains reports, proxy and information statements and other information regarding issuers that file electronically with the SEC. Our SEC filings are available on the SEC's website at www.sec.gov.

The SEC allows us to "incorporate by reference" the information we have filed with the SEC. This means that we can disclose important information to you without actually including the specific information in this prospectus by referring you to other documents filed separately with the SEC. The information incorporated by reference is an important part of this prospectus. Information that we later provide to the SEC, and which is deemed to be "filed" with the SEC, will automatically update information previously filed with the SEC, and may update or replace information in this prospectus and information previously filed with the SEC.

We incorporate by reference the documents listed below and any filings we make with the SEC under Sections 13(a), 13(c), 14, or 15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act") (excluding information deemed to be furnished and not filed with the SEC), after the date on which the registration statement was initially filed with the SEC (including all such documents that we may file with the SEC after the date the registration statement was initially filed and prior to the effectiveness of the registration statement) until all offerings under the registration statement of which this prospectus forms a part are completed or terminated:

These reports contain important information about us, our financial condition and our results of operations.

We make available free of charge on or through our website, solaris-energy.com, our filings with the SEC pursuant to Section 13(a) or 15(d) of the Exchange Act as soon as reasonably practicable after we electronically file such material with, or furnish it to, the SEC. We make our website content available for information purposes only. Information contained on our website is not incorporated by reference into this prospectus and does not constitute a part of this prospectus.

You may obtain copies of any of the documents incorporated by reference in this prospectus from the SEC through the SEC's website at the address provided above. You also may request a copy of any document incorporated by reference in this prospectus (including exhibits to those documents specifically incorporated by reference in this prospectus), at no cost, by contacting us at:

Solaris Energy Infrastructure, Inc.

Attention: Investor Relations

9651 Katy Freeway, Suite 300

Houston, Texas 77024

(281) 501-3070

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CAUTIONARY STATEMENT REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the documents incorporated by reference herein include "forward-looking statements" within the meaning of Section 27A of the Securities Act and Section 21E of the Exchange Act, which involve risks, uncertainties and assumptions. Statements that are predictive in nature, that depend upon or refer to future events or conditions or that include the words "believe," "expect," "anticipate," "intend," "estimate," "could," "may," "continue," "predict," "potential" and other expressions that are predictions of or indicate future events and trends and that do not relate to historical matters identify forward-looking statements. Our forward-looking statements include statements about our business strategy, our industry, our future profitability, our expected capital expenditures and the impact of such expenditures on our performance, management changes, current and potential future long-term contracts, the costs of being a publicly traded corporation, our capital programs and our future business and financial performance. In addition, our forward-looking statements address the various risks and uncertainties associated with extraordinary market environments and the expected impact on our businesses, results of operations and earnings.

A forward-looking statement may include a statement of the assumptions or bases underlying the forward-looking statement. We believe that we have chosen these assumptions or bases in good faith and that they are reasonable. You are cautioned not to place undue reliance on any forward-looking statements. You should also understand that it is not possible to predict or identify all such factors and should not consider the following list to be a complete statement of all potential risks and uncertainties. Factors that could cause our actual results to differ materially from the results contemplated by such forward-looking statements include:

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All forward-looking statements speak only as of the date of this prospectus. You should not place undue reliance on our forward-looking statements. Although forward-looking statements reflect our good faith beliefs at the time they are made, forward-looking statements involve known and unknown risks, uncertainties and other factors, including the factors described under Item 1A, "Risk Factors" in our Annual Report on Form 10-K for the year ended December 31, 2024 and under Part II, Item 1A. "Risk Factors" of our Quarterly Reports on Form 10-Q for the quarters ended March 31, 2025 and June 30, 2025, this prospectus and in our other filings with the SEC, which may cause our actual results, performance or achievements to differ materially from anticipated future results, performance or achievements expressed or implied by such forward-looking statements. We undertake no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events, changed circumstances or otherwise, unless required by law.

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ABOUT SOLARIS ENERGY INFRASTRUCTURE, INC.

We provide mobile and scalable equipment-based solutions for use in distributed power generation as well as the management of raw materials used in the completion of oil and natural gas wells. Headquartered in Houston, Texas, Solaris serves multiple U.S. end markets, including energy, data centers, and other commercial and industrial sectors. Solaris delivers these offerings through its Solaris Power Solutions and Solaris Logistics Solutions business segments.

Solaris Power Solutions, recently established following the acquisition of Mobile Energy Rentals LLC ("MER"), provides mobile power generation solutions through equipment lease arrangements. On September 11, 2024, Solaris, through its subsidiary Solaris LLC, completed the acquisition of MER (the "MER Acquisition"). MER operates throughout the United States, providing configurable sets of primarily natural gas-powered mobile turbines and ancillary equipment to energy, data center, and other commercial and industrial end-markets. This acquisition provided Solaris entry into the large and growing distributed power solutions market, both enhancing our position as a mobile equipment and logistics solution provider to the oil and gas industry and also diversifying our end market exposure.

Solaris Logistics Solutions designs and manufactures specialized equipment, which combined with field technician support, last mile and mobilization logistics services and software solutions, enables the Company to provide a service offering that helps oil and natural gas operators and their suppliers drive efficiencies that reduce operational footprint and costs during the completion phase of well development. The Company services most active oil and natural gas basins in the United States.

Our principal executive offices are located at 9651 Katy Freeway, Suite 300, Houston, Texas 77024, and our telephone number is (281) 501-3070. Our website address is solaris-energy.com. The information on our website is not part of this prospectus.

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RISK FACTORS

An investment in our securities involves a significant degree of risk. Before you invest in our securities, you should carefully consider those risk factors included in our most recent Annual Report on Form 10-K, any subsequently filed Quarterly Reports on Form 10-Q and any subsequently filed Current Reports on Form 8-K, each of which is incorporated herein by reference, and those risk factors that may be included in any applicable prospectus supplement, together with all of the other information included in this prospectus, any prospectus supplement and the documents we incorporate by reference, in evaluating an investment in our securities. If any of these risks were actually to occur, our business, financial condition or results of operations could be materially adversely affected. Additional risks not presently known to us or that we currently believe are immaterial may also significantly impair our business operations and financial condition. Please read "Cautionary Statement Regarding Forward-Looking Statements."

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USE OF PROCEEDS

Unless otherwise specified in an accompanying prospectus supplement, we will use the net proceeds we receive from the sale of the securities covered by this prospectus for general corporate purposes, which may include, among other things, paying or refinancing all or a portion of our indebtedness at the time, funding acquisitions, capital expenditures and working capital.

The actual application of the net proceeds from the sale of any particular offering of securities using this prospectus will be described in the applicable prospectus supplement relating to such offering.

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DESCRIPTION OF DEBT SECURITIES

General

Solaris Energy Infrastructure, Inc. ("Solaris Inc.") may issue debt securities in one or more series. When used in this "Description of Debt Securities" section, unless we state otherwise or the context clearly indicates otherwise, references to the Company," "we," "us," and "our" refer to Solaris Energy Infrastructure, Inc. and not any of its subsidiaries. We may issue senior or subordinated debt securities. Neither the senior debt securities nor the subordinated debt securities will be secured by any of our property or assets. Thus, by owning a debt security, you will be one of our unsecured creditors.

The senior debt securities will constitute part of our senior debt, will be issued under a senior debt indenture described below and will rank equally with all of our other unsecured and unsubordinated debt. The subordinated debt securities will constitute part of our subordinated debt, will be issued under a subordinated debt indenture described below and will be subordinate in right of payment to all of our "senior debt," as defined in the indenture with respect to such subordinated debt securities. The prospectus supplement for any series of subordinated debt securities or the information incorporated in this prospectus by reference will indicate the approximate amount of senior debt outstanding as of the end of the then most recent fiscal quarter. Neither indenture will limit our ability to incur additional senior debt or other indebtedness.

When we refer to "debt securities" in this prospectus, we mean both the senior debt securities and the subordinated debt securities. When we refer to a "debt security" in this prospectus, we mean either a senior debt security or a subordinated debt security.

Solaris Inc. is a holding company and has no material assets other than its interests in Solaris LLC. Solaris Inc. has no independent means of generating revenue. We conduct all of our operations through Solaris LLC and its subsidiaries and expect that we will continue to do so. The debt securities will not be guaranteed by any of our existing or future subsidiaries. Our subsidiaries are separate and distinct legal entities and have no obligation, contingent or otherwise, to pay any amounts due with respect to the debt securities or to make any funds available therefor, whether by dividends, loans or other payments.

The debt indentures and their associated documents, including your debt security, will contain the full legal text of the matters described in this section and your prospectus supplement. We have filed forms of the indentures with the SEC as exhibits to our registration statement, of which this prospectus is a part. See "Where You Can Find More Information" in this prospectus for information on how to obtain copies of them.

This section and your prospectus supplement summarize material terms of the indentures and your debt security. They do not, however, describe every aspect of the indentures and your debt security. For example, in this section and your prospectus supplement, we use terms that have been given special meaning in the indentures, but we describe the meaning for only the more important of those terms. Your prospectus supplement will have a more detailed description of the specific terms of your debt security.

Indentures

The senior debt securities will be issued under an indenture (the "senior debt indenture") and subordinated debt securities will be issued under an indenture (the "subordinated debt indenture" and, together with the senior debt indenture, the "indentures" and each, an "indenture"). Each indenture is a contract between us and the respective trustee. The indentures are substantially identical, except for certain provisions including those relating to subordination, which are included only in the indenture related to subordinated debt securities.

The trustee under each indenture has two main roles:

First, the trustee can enforce your rights against us if we default. There are some limitations on the extent to which the trustee acts on your behalf, which we describe later under "- Default, Remedies and Waiver of Default."

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Second, the trustee performs administrative duties for us, such as sending you interest payments and notices.

When we refer to the "indenture" or the "trustee" with respect to any debt securities, we mean the indenture under which those debt securities are issued and the trustee under that indenture.

Series of Debt Securities

We may issue as many distinct debt securities or series of debt securities under either indenture as we wish. This section summarizes terms of the securities that apply generally to all debt securities and series of debt securities. The provisions of each indenture allow us not only to issue debt securities with terms different from those of debt securities previously issued under that indenture, but also to "reopen" a previously issued series of debt securities and issue additional debt securities of that series. We will describe most of the financial and other specific terms of your debt security, whether it is a series of the senior debt securities or the subordinated debt securities, in your prospectus supplement. Those terms may vary from the terms described here.

As you read this section, please remember that the specific terms of your debt security as described in your prospectus supplement will supplement and, if applicable, modify or replace the general terms described in this section. If there are any differences between your prospectus supplement and this prospectus with respect to your debt security, your prospectus supplement will control. Thus, the statements we make in this section may not apply to your debt security.

When we refer to a "series of debt securities," we mean a series of debt securities issued under the applicable indenture. When we refer to "your debt security," we mean the series of debt securities you purchase. When we refer to "your prospectus supplement," we mean the prospectus supplement describing the specific terms of your debt security. The terms used in your prospectus supplement will have the meanings described in this prospectus, unless otherwise specified.

Amounts of Issuances

Neither indenture will limit the aggregate amount of debt securities that we may issue or the number of series or the aggregate amount of any particular series. We may issue debt securities and other securities at any time without your consent and without notifying you. The indentures and the debt securities will not limit our ability to incur other indebtedness or to issue other securities other than as specified in your debt security, as applicable. Also, unless otherwise specified below or in your prospectus supplement, we are not subject to financial or similar restrictions by the terms of the debt securities.

Principal Amount, Stated Maturity and Maturity

Unless otherwise stated, the principal amount of a debt security means the principal amount payable at its stated maturity, unless that amount is not determinable, in which case the principal amount of a debt security is its face amount. The term "stated maturity" with respect to any debt security means the day on which the principal amount of your debt security is scheduled to become due. The principal may become due sooner, by reason of redemption, acceleration after a default or otherwise in accordance with the terms of the debt security. The day on which the principal actually becomes due, whether at the stated maturity or earlier, is called the "maturity" of the principal. We also use the terms "stated maturity" and "maturity" to refer to the days when other payments become due. For example, we may refer to a regular interest payment date when an installment of interest is scheduled to become due as the "stated maturity" of that installment. When we refer to the "stated maturity" or the "maturity" of a debt security without specifying a particular payment, we mean the stated maturity or maturity, as the case may be, of the principal.

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Specific Terms of Debt Securities

Your prospectus supplement will describe the specific terms of your debt security, which will include some or all of the following:

Governing Law

The indentures and the debt securities will be governed by New York law.

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Form of Debt Securities

We will issue each debt security only in registered form, without coupons, unless we specify otherwise in the applicable prospectus supplement. In addition, we will issue each debt security in global - i.e., book-entry - form only, unless we specify otherwise in the applicable prospectus supplement. Debt securities in book-entry form will be represented by a global security registered in the name of a depositary, which will be the holder of all the debt securities represented by the global security. Those who own beneficial interests in a global debt security will do so through participants in the depositary's securities clearance system, and the rights of these indirect owners will be governed solely by the applicable procedures of the depositary and its participants. References to "holders" in this section mean those who own debt securities registered in their own names, on the books that we or the trustee maintain for this purpose, and not those who own beneficial interests in debt securities registered in street name or in debt securities issued in book-entry form through one or more depositaries.

Unless otherwise indicated in the prospectus supplement, the following is a summary of the depositary arrangements applicable to debt securities issued in global form and for which DTC acts as depositary.

Each global debt security will be deposited with, or on behalf of, DTC, as depositary, or its nominee, and registered in the name of a nominee of DTC. Except under the limited circumstances described below, global debt securities are not exchangeable for definitive certificated debt securities.

Ownership of beneficial interests in a global debt security is limited to institutions that have accounts with DTC or its nominee, or persons that may hold interests through those participants. In addition, ownership of beneficial interests by participants in a global debt security will be evidenced only by, and the transfer of that ownership interest will be effected only through, records maintained by DTC or its nominee for a global debt security. Ownership of beneficial interests in a global debt security by persons that hold those interests through participants will be evidenced only by, and the transfer of that ownership interest within that participant will be effected only through, records maintained by that participant. DTC has no knowledge of the actual beneficial owners of the debt securities. Beneficial owners will not receive written confirmation from DTC of their purchase, but beneficial owners are expected to receive written confirmations providing details of the transaction, as well as periodic statements of their holdings, from the participants through which the beneficial owners entered the transaction. The laws of some jurisdictions require that certain purchasers of securities take physical delivery of securities they purchase in definitive form. These laws may impair your ability to transfer beneficial interests in a global debt security.

We will make payment of principal of, and interest on, debt securities represented by a global debt security registered in the name of or held by DTC or its nominee to DTC or its nominee, as the case may be, as the registered owner and holder of the global debt security representing those debt securities. DTC has advised us that upon receipt of any payment of principal of, or interest on, a global debt security, DTC immediately will credit accounts of participants on its book-entry registration and transfer system with payments in amounts proportionate to their respective interests in the principal amount of that global debt security, as shown in the records of DTC. Payments by participants to owners of beneficial interests in a global debt security held through those participants will be governed by standing instructions and customary practices, as is now the case with securities held for the accounts of customers in bearer form or registered in "street name," and will be the sole responsibility of those participants, subject to any statutory or regulatory requirements that may be in effect from time to time.

Neither we, any trustee nor any of our respective agents will be responsible for any aspect of the records of DTC, any nominee or any participant relating to, or payments made on account of, beneficial interests in a permanent global debt security or for maintaining, supervising or reviewing any of the records of DTC, any nominee or any participant relating to such beneficial interests.

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A global debt security is exchangeable for definitive certificated debt securities registered in the name of, and a transfer of a global debt security may be registered to, any person other than DTC or its nominee, only if:

Any global debt security that is exchangeable pursuant to the preceding paragraph will be exchangeable in whole for definitive certificated debt securities in registered form, of like tenor and of an equal aggregate principal amount as the global debt security, in denominations specified in the applicable prospectus supplement, if other than $2,000 and multiples of $1,000. The definitive debt securities will be registered by the registrar in the name or names instructed by DTC. We expect that these instructions may be based upon directions received by DTC from its participants with respect to ownership of beneficial interests in the global debt security.

Except as provided above or in your prospectus supplement, owners of the beneficial interests in a global debt security will not be entitled to receive physical delivery of debt securities in definitive certificated form and will not be considered the holders of debt securities for any purpose under the indentures. Except as provided above, no global debt security shall be exchangeable except for another global debt security of like denomination and tenor to be registered in the name of DTC or its nominee. Accordingly, each person owning a beneficial interest in a global debt security must rely on the procedures of DTC and, if that person is not a participant, on the procedures of the participant through which that person owns its interest, to exercise any rights of a holder under the global debt security or the indentures.

We understand that, under existing industry practices, in the event that we request any action of holders, or an owner of a beneficial interest in a global debt security desires to give or take any action that a holder is entitled to give or take under the debt securities or the indentures, DTC would authorize the participants holding the relevant beneficial interests to give or take that action. Additionally, those participants would authorize beneficial owners owning through those participants to give or take that action or would otherwise act upon the instructions of beneficial owners owning through them.

DTC has advised us that it is a limited-purpose trust company organized under the laws of the State of New York, a "banking organization" within the meaning of the New York Banking Law, a member of the Federal Reserve System, a "clearing corporation" within the meaning of the New York Uniform Commercial Code, and a "clearing agency" registered under the Exchange Act. DTC was created to hold securities of its participants and to facilitate the clearance and settlement of transactions among its participants in securities through electronic book-entry changes in accounts of the participants. By doing so, DTC eliminates the need for physical movement of securities certificates.

DTC's participants include securities brokers and dealers, banks, trust companies, clearing corporations, and certain other organizations. DTC is a wholly owned subsidiary of The Depository Trust & Clearing Corporation (DTCC); DTCC is the holding company for DTC, National Securities Clearing Corporation and Fixed Income Clearing Corporation, all of which are registered clearing agencies; and DTCC is owned by the users of its regulated subsidiaries. Access to DTC's book-entry system is also available to others, such as banks, brokers, dealers, and trust companies that clear through or maintain a custodial relationship with a participant, either directly or indirectly. The rules applicable to DTC and its participants are on file with the SEC.

Investors may hold interests in the debt securities outside the U.S. through the Euroclear System ("Euroclear") or Clearstream Banking ("Clearstream") if they are participants in those systems, or indirectly through organizations which are participants in those systems. Euroclear and Clearstream will hold interests on behalf of their participants through customers' securities accounts in Euroclear's and Clearstream's names on the books of their respective depositaries, which in turn will hold such interests in customers' securities accounts in

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the depositaries' names on the books of DTC. All securities in Euroclear or Clearstream are held on a fungible basis without attribution of specific certificates to specific securities clearance accounts.

The following is based on information furnished by Euroclear or Clearstream, as the case may be. Euroclear has advised us that:

Clearstream has advised us that:

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We have provided the descriptions herein of the operations and procedures of DTC, Euroclear and Clearstream solely as a matter of convenience. These operations and procedures are solely within the control of DTC, Euroclear and Clearstream and are subject to change by them from time to time. We believe that the sources from which the information in this section and elsewhere in this prospectus concerning DTC, Euroclear, Euroclear SA/NV, Euroclear Clearance Systems S.C., Euroclear's system, Clearstream and Clearstream's system has been obtained are reliable, but neither we, any underwriters nor the trustee takes any responsibility for the accuracy of the information.

Initial settlement for the securities will be made in immediately available funds. Secondary market trading between DTC participants will occur in the ordinary way in accordance with DTC's rules and will be settled in immediately available funds. Secondary market trading between Euroclear participants and/or Clearstream participants will occur in the ordinary way in accordance with the applicable rules and operating procedures of Euroclear and Clearstream, as applicable, and will be settled using the procedures applicable to conventional eurobonds in immediately available funds.

Cross-market transfers between persons holding directly or indirectly through DTC, on the one hand, and directly or indirectly through Euroclear participants or Clearstream participants, on the other, will be effected in DTC in accordance with DTC rules on behalf of the relevant European international clearing system by its U.S. depositary; however, such cross-market transactions will require delivery of instructions to the relevant European international clearing system by the counterparty in such system in accordance with its rules and procedures and within its established deadlines (European time). The relevant European international clearing system will, if the transaction meets its settlement requirements, deliver instructions to its U.S. depositary to take action to effect final settlement on its behalf by delivering or receiving securities in DTC, and making or receiving payment in accordance with normal procedures for same-day funds settlement applicable to DTC. Euroclear participants and Clearstream participants may not deliver instructions directly to their respective U.S. depositaries.

Because of time-zone differences, credits of securities received in Euroclear or Clearstream as a result of a transaction with a DTC participant will be made during subsequent securities settlement processing and dated the business day following the DTC settlement date. Credits or any transactions in securities settled during this processing will be reported to the relevant Euroclear or Clearstream participants on that following business day. Cash received in Euroclear or Clearstream as a result of sales of debt securities by or through a Euroclear participant or a Clearstream participant to a DTC participant will be received with value on the DTC settlement date but will be available in the relevant Euroclear or Clearstream cash account only as of the business day following settlement in DTC.

Although DTC, Euroclear and Clearstream have agreed to the foregoing procedures to facilitate transfers of securities among participants of DTC, Euroclear and Clearstream, they are under no obligation to perform or continue to perform these procedures and these procedures may be discontinued at any time.

Redemption or Repayment

If there are any provisions regarding redemption or repayment applicable to your debt security, we will describe them in your prospectus supplement. We or our affiliates may purchase debt securities from investors who are willing to sell from time to time, either in the open market at prevailing prices or in private transactions at negotiated prices. Debt securities that we or they purchase may, at our discretion, be held, resold or canceled.

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Mergers and Similar Transactions

We are generally permitted under the indentures to merge or consolidate with another corporation or other entity. We are also permitted under the indentures to sell all or substantially all of our assets to another corporation or other entity. With regard to any series of debt securities and other than as set forth in your prospectus supplement, however, we may not take any of these actions unless all the following conditions, among other things, are met:

If the conditions described above are satisfied with respect to the debt securities of any series, we will not need to obtain the approval of the holders of those debt securities in order to merge or consolidate or to sell all or substantially all our assets. Also, these conditions will apply only if we wish to merge or consolidate with another entity or sell all or substantially all of our assets to another entity. We will not need to satisfy these conditions if we enter into other types of transactions, including any transaction in which we acquire the stock or assets of another entity, any transaction that involves a change of control of the Company but in which we do not merge or consolidate and any transaction in which we sell less than substantially all our assets.

The successor entity will be substituted for the Company with respect to the debt securities of any series and under the indenture with the same effect as if it had been an original party to the indenture, and, except in the case of a lease, the Company will be relieved from any further obligations and covenants under the indenture.

Subordination Provisions

Holders of subordinated debt securities should recognize that contractual provisions in the subordinated debt indenture may prohibit us from making payments on those securities. Subordinated debt securities are subordinate and junior in right of payment, to the extent and in the manner stated in the subordinated debt indenture, to all of our senior debt, as defined in the subordinated debt indenture, including all debt securities we have issued and will issue under the senior debt indenture.

The subordinated debt indenture will define "senior debt" as:

Notwithstanding the foregoing, "senior debt" will not include: (i) equity interests; (ii) any liability for taxes; (iii) any indebtedness to any of our subsidiaries or affiliates; (iv) any trade payables; or (v) any indebtedness incurred in violation of the subordinated debt indenture.

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We may modify the subordination provisions, including the definition of senior debt, with respect to one or more series of subordinated debt securities. Such modifications will be set forth in the applicable prospectus supplement.

The subordinated debt indenture provides that, unless all principal of and any premium or interest on the senior debt has been paid in full, no payment or other distribution may be made in respect of any subordinated debt securities in the following circumstances:

(i) in the event of any insolvency or bankruptcy proceedings, or any receivership, liquidation, reorganization, assignment for creditors or other similar proceedings or events involving us or our assets;

(ii) in the event and during the continuation of any default in the payment of principal of, and any premium and interest on, any senior debt beyond any applicable grace period or (ii) in the event that any event of default with respect to any senior debt has occurred and is continuing, permitting the holders of that senior debt (or a trustee) to accelerate the maturity of that senior debt, whether or not the maturity is in fact accelerated (unless, in the case of (i) or (ii), the payment default or event of default has been cured or waived or ceased to exist and any related acceleration has been rescinded) or (iii) in the event that any judicial proceeding is pending with respect to a payment default or event of default described in (i) or (ii); or

(iii) in the event that any subordinated debt securities have been declared due and payable before their stated maturity.

If the trustee under the subordinated debt indenture or any holders of the subordinated debt securities receive any payment or distribution that is prohibited under the subordination provisions, then the trustee or the holders will have to repay that money to the holders of the senior debt.

Even if the subordination provisions prevent us from making any payment when due on the subordinated debt securities of any series, we will be in default on our obligations under that series if we do not make the payment when due. This means that the trustee under the subordinated debt indenture and the holders of that series can take action against us, but they will not receive any money until the claims of the holders of senior debt have been fully satisfied.

The subordinated debt indenture allows the holders of senior debt to obtain a court order requiring us and any holder of subordinated debt securities to comply with the subordination provisions.

Defeasance, Covenant Defeasance and Satisfaction and Discharge

When we use the term defeasance, we mean discharge from some or all of our obligations under the applicable indenture. Except as otherwise specified in the applicable prospectus supplement, if we deposit with the trustee funds or government securities, or if so provided in your prospectus supplement, obligations other than government securities, sufficient to make payments on any series of debt securities on the dates those payments are due and payable and other specified conditions are satisfied, then, at our option, either of the following will occur:

If we defease any series of debt securities, the holders of such securities will not be entitled to the benefits of the applicable indenture, except for our obligations to register the transfer or exchange of such securities, replace stolen, lost or mutilated securities or maintain paying agencies and hold moneys for payment in trust. In case of covenant defeasance, our obligation to pay principal of, and any premium and interest on, the applicable series of debt securities will also survive.

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We will be required to deliver to the trustee an opinion of counsel that the deposit and related defeasance would not cause the holders of the applicable series of debt securities to recognize gain or loss for U.S. federal income tax purposes. If we elect legal defeasance, that opinion of counsel must be based upon a ruling from the United States Internal Revenue Service or a change in law to that effect.

In addition, except as otherwise specified in the applicable prospectus supplement, we may satisfy and discharge all our obligations under the indenture with respect to debt securities of any series, other than our obligation to register the transfer of and exchange debt securities of that series, provided that we either:

No Personal Liability

No past, present or future director, officer, employee, incorporator, member, manager, partner (whether general or limited), stockholder or stockholder of the Company, as such, will have any liability for any obligations of us under the debt securities or the indentures or for any claim based on, in respect of, or by reason of, such obligations or their creation. Each holder of debt securities by accepting a debt security waives and releases all such liability. The waiver and release are part of the consideration for issuance of the debt securities. The waiver may not be effective to waive liabilities under the federal securities laws.

Default, Remedies and Waiver of Default

You will have special rights if an event of default with respect to your debt security occurs and is continuing, as described in this subsection.

Events of Default

Unless your prospectus supplement says otherwise, when we refer to an event of default with respect to any series of debt securities, we mean any of the following:

We may change, eliminate, or add to the events of default with respect to any particular series or any particular debt security or debt securities within a series, as indicated in the applicable prospectus supplement.

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Remedies if an Event of Default Occurs

If you are the holder of a subordinated debt security, all the remedies available upon the occurrence of an event of default under the subordinated debt indenture will be subject to the restrictions on the subordinated debt securities described above under "- Subordination Provisions."

Except as otherwise specified in the applicable prospectus supplement, if an event of default has occurred with respect to any series of debt securities and has not been cured or waived, the trustee or the holders of not less than 25% in principal amount of all debt securities of that series then outstanding may declare the entire principal amount of the debt securities of that series to be due immediately. Except as otherwise specified in the applicable prospectus supplement, if the event of default occurs because of events in bankruptcy, insolvency or reorganization relating to the Company, the entire principal amount of the debt securities of that series will be automatically accelerated, without any action by the trustee or any holder.

Each of the situations described above is called an acceleration of the stated maturity of the affected series of debt securities. Except as otherwise specified in the applicable prospectus supplement, if the stated maturity of any series is accelerated and a judgment for payment has not yet been obtained, the holders of a majority in principal amount of the debt securities of that series may cancel the acceleration for the entire series.

If an event of default occurs, the trustee will have special duties. In that situation, the trustee will be obligated to use those of its rights and powers under the relevant indenture, and to use the same degree of care and skill in doing so, that a prudent person would use in that situation in conducting his or her own affairs.

Except as described in the prior paragraph, the trustee is not required to take any action under the relevant indenture at the request of any holders unless the holders offer the trustee reasonable protection from expenses and liability. This is called an indemnity. If the trustee is provided with an indemnity reasonably satisfactory to it, the holders of a majority in principal amount of all debt securities of the relevant series may direct the time, method and place of conducting any lawsuit or other formal legal action seeking any remedy available to the trustee with respect to that series. These majority holders may also direct the trustee in performing any other action under the relevant indenture with respect to the debt securities of that series.

Before you bypass the trustee and bring your own lawsuit or other formal legal action or take other steps to enforce your rights or protect your interests relating to any debt security, all of the following must occur:

You are entitled at any time, however, to bring a lawsuit for the payment of money due on your debt security on or after its stated maturity (or, if your debt security is redeemable, on or after its redemption date).

Book-entry and other indirect owners should consult their banks or brokers for information on how to give notice or direction to or make a request of the trustee and how to declare or cancel an acceleration of the maturity.

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Waiver of Default

The holders of not less than a majority in principal amount of the debt securities of any series may waive a default for all debt securities of that series. If this happens, the default will be treated as if it has not occurred. No one can waive a payment default on any debt security, however, without the approval of the particular holder of that debt security.

Annual Information about Defaults to the Trustee

We will furnish each trustee every year a written statement of two of our officers certifying that to their knowledge we are in compliance with the applicable indenture and the debt securities issued under it, or else specifying any default under the applicable indenture.

Modifications and Waivers

There are four types of changes we can make to either indenture and the debt securities or series of debt securities issued under that indenture.

Changes Requiring Each Holder's Approval

First, there are changes that cannot be made without the approval of each holder of a debt security affected by the change under the applicable indenture, including, among others:

Changes Not Requiring Approval

The second type of change does not require any approval by holders of the debt securities affected. These changes are limited to clarifications and changes that would not adversely affect any debt securities of any series in any material respect. Nor do we need any approval to make changes that affect only debt securities to be issued under the applicable indenture after the changes take effect. We may also make changes or obtain waivers that do not adversely affect a particular debt security, even if they affect other debt securities. In those cases, we

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do not need to obtain the approval of the holder of the unaffected debt security; we need only obtain any required approvals from the holders of the affected debt securities. We may also make changes to conform the text of the applicable indenture or any debt securities to any provision of the "Description of Debt Securities" in this prospectus or the comparable section in your prospectus supplement, to the extent such provision was intended to be a verbatim recitation of a provision of such indenture or debt securities.

Modification of Subordination Provisions

We may not amend the indenture related to subordinated debt securities to alter the subordination of any outstanding subordinated debt securities without the written consent of each holder of senior debt then outstanding who would be adversely affected (or the group or representative thereof authorized or required to consent thereto pursuant to the instrument creating or evidencing, or pursuant to which there is outstanding, such senior debt). In addition, we may not modify the subordination provisions of the indenture related to subordinated debt securities in a manner that would adversely affect the subordinated debt securities of any one or more series then outstanding in any material respect, without the consent of the holders of a majority in aggregate principal amount of all affected series then outstanding, voting together as one class (and also of any affected series that by its terms is entitled to vote separately as a series, as described below).

Changes Requiring Majority Approval

Any other change to a particular indenture and the debt securities issued under that indenture would require the following approval:

in each case, except as may otherwise be provided pursuant to such indenture for all or any particular debt securities of any series. This means that modification of terms with respect to certain securities of a series could be effectuated without obtaining the consent of the holders of a majority in principal amount of other securities of such series that are not affected by such modification.

The same majority approval would be required for us to obtain a waiver of any of our covenants in either indenture. Our covenants include the promises we make about merging or selling substantially all of our assets, which we describe above under "- Mergers and Similar Transactions." If the holders approve a waiver of a covenant, we will not have to comply with it. The holders, however, cannot approve a waiver of any provision in a particular debt security, or in the applicable indenture as it affects that debt security, that we cannot change without the approval of the holder of that debt security as described above in "- Changes Requiring Each Holder's Approval," unless that holder approves the waiver.

We may issue particular debt securities or a particular series of debt securities, as applicable, that are entitled, by their terms, to separately approve matters (for example, modification or waiver of provisions in the applicable indenture) that would also, or otherwise, require approval of holders of a majority in principal amount of all affected debt securities of all affected series issued under such indenture voting together as a single class. Any such affected debt securities or series of debt securities would be entitled to approve such matters (i) pursuant to such special rights by consent of holders of a majority in principal amount of such affected debt securities or series of debt securities voting separately as a class and (ii) in addition, as described above, except

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as may otherwise be provided pursuant to the applicable indenture for such debt securities or series of debt securities, by consent of holders of a majority in principal amount of such affected debt securities or series of debt securities and all other affected debt securities of all series issued under such indenture voting together as one class for this purpose. We may issue series or debt securities of a series having these or other special voting rights without obtaining the consent of or giving notice to holders of outstanding debt securities or series.

Book-entry and other indirect owners should consult their banks or brokers for information on how approval may be granted or denied if we seek to change an indenture or any debt securities or request a waiver.

Special Rules for Action by Holders

Only holders of outstanding debt securities of the applicable series will be eligible to take any action under the applicable indenture, such as giving a notice of default, declaring an acceleration, approving any change or waiver or giving the trustee an instruction with respect to debt securities of that series. Also, we will count only outstanding debt securities in determining whether the various percentage requirements for taking action have been met. Any debt securities owned by us or any of our affiliates or surrendered for cancellation or for payment or redemption, for which money has been set aside in trust, are not deemed to be outstanding. Any required approval or waiver must be given by written consent.

In some situations, we may follow special rules in calculating the principal amount of debt securities that are to be treated as outstanding for the purposes described above. This may happen, for example, if the principal amount is payable in a non-U.S. dollar currency, increases over time or is not to be fixed until maturity.

We will generally be entitled to set any day as a record date for the purpose of determining the holders that are entitled to take action under either indenture. In certain limited circumstances, only the trustee will be entitled to set a record date for action by holders. If we or the trustee sets a record date for an approval or other action to be taken by holders, that vote or action may be taken only by persons or entities who are holders on the record date and must be taken during the period that we specify for this purpose, or that the trustee specifies if it sets the record date. We or the trustee, as applicable, may shorten or lengthen this period from time to time. This period, however, may not extend beyond the 180th day after the record date for the action. In addition, record dates for any global debt security may be set in accordance with procedures established by the depositary from time to time. Accordingly, record dates for global debt securities may differ from those for other debt securities.

Form, Exchange and Transfer

If any debt securities cease to be issued in registered global form, they will be issued:

Holders may exchange their debt securities for debt securities of smaller denominations or combined into fewer debt securities of larger denominations, as long as the total principal amount is not changed. You may not exchange your debt securities for securities of a different series or having different terms, unless your prospectus supplement and the supplemental indenture with respect to your debt securities provide for such exchange.

Holders may exchange or transfer their debt securities at the office of the trustee. They may also replace lost, stolen, destroyed or mutilated debt securities at that office. We have appointed the trustee to act as our agent for registering debt securities in the names of holders and transferring and replacing debt securities. We may appoint another entity to perform these functions or perform them ourselves.

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Holders will not be required to pay a service charge to transfer or exchange their debt securities, but they may be required to pay for any tax or other governmental charge associated with the exchange or transfer. The transfer or exchange, and any replacement, will be made only if our transfer agent is satisfied with the holder's proof of legal ownership. The transfer agent may require an indemnity before replacing any debt securities.

If we have designated additional transfer agents for your debt security, they will be named in your prospectus supplement. We may appoint additional transfer agents or cancel the appointment of any particular transfer agent. We may also approve a change in the office through which any transfer agent acts.

If the debt securities of any series are redeemable and we redeem less than all those debt securities, we may block the transfer or exchange of those debt securities during the period beginning 15 days before the day we mail the notice of redemption and ending on the day of that mailing, in order to freeze the list of holders to prepare the mailing. We may also refuse to register transfers of or exchange any debt security selected for redemption, except that we will continue to permit transfers and exchanges of the unredeemed portion of any debt security being partially redeemed.

If a debt security is issued as a global debt security, only DTC or other depositary will be entitled to transfer and exchange the debt security as described in this subsection because the depositary will be the sole holder of the debt security.

The rules for exchange described above apply to exchange of debt securities for other debt securities of the same series and kind. If a debt security is convertible, exercisable or exchangeable into or for a different kind of security, such as one that we have not yet issued, or for other property, the rules governing that type of conversion, exercise or exchange will be described in the applicable prospectus supplement.

Payments

We will pay interest, principal and other amounts payable with respect to the debt securities of any series to the holders of record of those debt securities as of the record dates and otherwise in the manner specified below or in the prospectus supplement for that series.

We will make payments on a global debt security in accordance with the applicable policies of the depositary as in effect from time to time. Under those policies, we will pay directly to the depositary, or its nominee, and not to any indirect owners who own beneficial interests in the global debt security. An indirect owner's right to receive those payments will be governed by the rules and practices of the depositary and its participants.

We will make payments on a debt security in non-global, registered form as follows. We will pay interest that is due on an interest payment date by check mailed on the interest payment date to the holder at his or her address shown on the trustee's records as of the close of business on the regular record date. We will make all other payments by check at the paying agent described below, against surrender of the debt security. All payments by check will be made in next-day funds - i.e., funds that become available on the day after the check is cashed.

Alternatively, if a non-global debt security has a face amount of at least $1,000,000 and the holder asks us to do so, we will pay any amount that becomes due on the debt security by wire transfer of immediately available funds to an account at a bank in New York City, on the due date. To request wire payment, the holder must give the paying agent appropriate wire transfer instructions at least five business days before the requested wire payment is due. In the case of any interest payment due on an interest payment date, the instructions must be given by the person or entity who is the holder on the relevant regular record date. In the case of any other payment, payment will be made only after the debt security is surrendered to the paying agent. Any wire instructions, once properly given, will remain in effect unless and until new instructions are given in the manner described above.

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Book-entry and other indirect owners should consult their banks or brokers for information on how they will receive payments on their debt securities.

Regardless of who acts as paying agent, all money paid by us to a paying agent that remains unclaimed at the end of two years after the amount is due to a holder will be repaid to us. After that two-year period, the holder may look only to us for payment and not to the trustee, any other paying agent or anyone else.

Paying Agents

We may appoint one or more financial institutions to act as our paying agents, at whose designated offices debt securities in non-global entry form may be surrendered for payment at their maturity. We call each of those offices a paying agent. We may add, replace or terminate paying agents from time to time. We may also choose to act as our own paying agent. We will specify in the prospectus supplement for your debt security the initial location of each paying agent for that debt security. We must notify the trustee of changes in the paying agents.

Notices

Notices to be given to holders of a global debt security will be given only to the depositary, in accordance with its applicable policies as in effect from time to time. Notices to be given to holders of debt securities not in global form will be sent by mail to the respective addresses of the holders as they appear in the trustee's records, and will be deemed given when mailed. Neither the failure to give any notice to a particular holder, nor any defect in a notice given to a particular holder, will affect the sufficiency of any notice given to another holder.

Book-entry and other indirect owners should consult their banks or brokers for information on how they will receive notices.

Our Relationship with the Trustee

The prospectus supplement for your debt security will describe any material relationships we may have with the trustee with respect to that debt security.

The same financial institution may initially serve as the trustee for our senior debt securities and subordinated debt securities. Consequently, if an actual or potential event of default occurs with respect to any of these securities, the trustee may be considered to have a conflicting interest for purposes of the Trust Indenture Act of 1939. In that case, the trustee may be required to resign under one or more of the indentures, and we would be required to appoint a successor trustee. For this purpose, a "potential" event of default means an event that would be an event of default if the requirements for giving us default notice or for the default having to exist for a specific period of time were disregarded.

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DESCRIPTION OF CAPITAL STOCK

Under our amended and restated certificate of incorporation, as amended, our authorized capital stock consists of 600,000,000 shares of Class A common stock, $0.01 par value per share 180,000,000 shares of Class B common stock, $0.00 par value per share ("Class B common stock"), and 50,000,000 shares of preferred stock, $0.01 par value per share. As of June 30, 2025, there were 30,455,600 shares of our Class A common stock outstanding, 30,136,749 shares of our Class B common stock outstanding and no shares of our preferred stock outstanding.

The following description of capital stock is based upon our amended and restated certificate of incorporation, our amended and restated bylaws, as amended, and applicable provisions of law. We have summarized certain portions of our amended and restated certificate of incorporation and amended and restated bylaws below. The summary is not complete and is subject to, and is qualified in its entirety by express reference to, the provisions of applicable law and to our amended and restated certificate of incorporation and amended and restated bylaws, which are filed as exhibits to the registration statement of which this prospectus is a part.

Class A Common Stock

Voting Rights. Holders of shares of Class A common stock are entitled to one vote per share held of record on all matters to be voted upon by the stockholders. The holders of shares of Class A common stock do not have cumulative voting rights in the election of directors.

Dividend Rights. Holders of shares of our Class A common stock are entitled to ratably receive dividends when and if declared by our board of directors out of funds legally available for that purpose, subject to any statutory or contractual restrictions on the payment of dividends and to any prior rights and preferences that may be applicable to any outstanding preferred stock.

Liquidation Rights. Upon our liquidation, dissolution, distribution of assets or other winding up, the holders of shares of Class A common stock are entitled to receive ratably the assets available for distribution to the stockholders after payment of liabilities and the liquidation preference of any of our outstanding shares of preferred stock.

Other Matters. The shares of Class A common stock have no preemptive or conversion rights and are not subject to further calls or assessment by us. There are no redemption or sinking fund provisions applicable to the Class A common stock. All outstanding shares of our Class A common stock, including the Class A common stock offered in this offering, are fully paid and non-assessable.

Class B Common Stock

Generally. Each member of Solaris Energy Infrastructure, LLC ("Solaris LLC") has received one share of Class B common stock for each unit of Solaris LLC (the "Solaris LLC Unit") that it holds. Accordingly, each member of Solaris LLC has a number of votes in the Company equal to the aggregate number of Solaris LLC Units that it holds.

Voting Rights. Holders of shares of our Class B common stock are entitled to one vote per share held of record on all matters to be voted upon by the stockholders. Holders of shares of our Class A common stock and Class B common stock vote together as a single class on all matters presented to our stockholders for their vote or approval, except with respect to the amendment of certain provisions of our amended and restated certificate of incorporation that would alter or change the powers, preferences or special rights of the Class B common stock so as to affect them adversely, which amendments must be adopted by a majority of the votes entitled to be cast by the holders of the shares affected by the amendment, voting as a separate class, or as otherwise required by applicable law.

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Dividend and Liquidation Rights. Holders of our Class B common stock do not have any right to receive dividends, unless the dividend consists of shares of our Class B common stock or of rights, options, warrants or other securities convertible or exercisable into or redeemable for shares of Class B common stock paid proportionally with respect to each outstanding share of our Class B common stock, and a dividend consisting of shares of Class A common stock or of rights, options, warrants or other securities convertible or exercisable into or redeemable for shares of Class A common stock on the same terms is simultaneously paid to the holders of Class A common stock. Holders of our Class B common stock do not have any right to receive a distribution upon the Company's liquidation or winding up.

Redemption Right. Each Member of Solaris LLC has received one share of Class B common stock for each Solaris LLC Unit that it holds. Pursuant to the second amended and restated limited liability company agreement of Solaris LLC, as amended from time to time (the "Solaris LLC Agreement"), each holder of Solaris LLC Units has the right to redeem all or a portion of its Solaris LLC Units (together with the surrender and delivery of an equal number of shares of Class B common stock) for an equal number of shares of Class A common stock, subject to customary conversion rate adjustments for stock splits, stock dividends and reclassifications, or, at the Company's election, an amount of cash as determined pursuant to the Solaris LLC Agreement.

Preferred Stock

Our amended and restated certificate of incorporation authorizes our board of directors, subject to any limitations prescribed by law, without further stockholder approval, to establish and to issue from time to time one or more classes or series of preferred stock, par value $0.01 per share, covering up to an aggregate of 50,000,000 shares of preferred stock. Each class or series of preferred stock will have the powers, preferences, rights, qualifications, limitations and restrictions determined by the board of directors, which may include, among others, dividend rights, liquidation preferences, voting rights, conversion rights, preemptive rights and redemption rights. Except as provided by law or in a preferred stock designation, the holders of preferred stock will not be entitled to vote at or receive notice of any meeting of stockholders.

Anti-Takeover Effects of Provisions of Our Amended and Restated Certificate of Incorporation,

Our Amended and Restated Bylaws and Delaware Law

Certain provisions of Delaware law and certain provisions of our amended and restated certificate of incorporation and our amended and restated bylaws described below could make it more difficult for a third party to acquire the Company by means of a tender offer, a proxy contest or otherwise; or removal of our incumbent officers and directors. These provisions may also have the effect of preventing changes in our management. It is possible that these provisions could make it more difficult to accomplish or could deter transactions that stockholders may otherwise consider to be in their best interest or in our best interests, including transactions that might result in a premium over the market price for our shares.

These provisions, summarized below, are expected to discourage coercive takeover practices and inadequate takeover bids. These provisions are also designed to encourage persons seeking to acquire control of us to first negotiate with us. We believe that the benefits of increased protection and our potential ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure us outweigh the disadvantages of discouraging these proposals because, among other things, negotiation of these proposals could result in an improvement of their terms.

Delaware Law

Our amended and restated certificate of incorporation provides that we are not governed by Section 203 of the Delaware General Corporation Law ("DGCL"), which, in the absence of such provisions, would have

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imposed additional requirements regarding mergers and other business combinations. Section 203 of the DGCL prohibits a Delaware corporation, including those whose securities are listed for trading on the New York Stock Exchange, from engaging in any business combination with any interested stockholder for a period of three years following the date that the stockholder became an interested stockholder, unless:

Our Amended and Restated Certificate of Incorporation and Our Amended and Restated Bylaws

Certain provisions of our amended and restated certificate of incorporation and amended and restated bylaws may delay or discourage transactions involving an actual or potential change in control or change in our management, including transactions in which stockholders might otherwise receive a premium for their shares, or transactions that our stockholders might otherwise deem to be in their best interests. Therefore, these provisions could adversely affect the price of our Class A common stock.

Among other things, our amended and restated certificate of incorporation and amended and restated bylaws:

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Corporate Opportunity

Under our amended and restated certificate of incorporation, to the extent permitted by law:

Forum Selection

Our amended and restated certificate of incorporation provides that unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware will, to the fullest extent permitted by applicable law, be the sole and exclusive forum for:

Our amended and restated certificate of incorporation also provides that any person or entity purchasing or otherwise acquiring any interest in shares of our capital stock will be deemed to have notice of, and to have consented to, this forum selection provision. Although we believe these provisions benefit us by providing increased consistency in the application of Delaware law for the specified types of actions and proceedings, the provisions may have the effect of discouraging lawsuits against our directors, officers, employees and agents.

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The enforceability of similar exclusive forum provisions in other companies' certificates of incorporation has been challenged in legal proceedings, and it is possible that, in connection with one or more actions or proceedings described above, a court could rule that this provision in our amended and restated certificate of incorporation is inapplicable or unenforceable.

The choice of forum provisions summarized above are not intended to, and would not, apply to suits brought to enforce any liability or duty created by the Securities Act or the Exchange Act or other claim for which the federal courts have exclusive jurisdiction. To the extent that any such claims may be based upon federal law claims, Section 27 of the Exchange Act creates exclusive federal jurisdiction over all suits brought to enforce any duty or liability created by the Exchange Act or the rules and regulations thereunder. Furthermore, Section 22 of the Securities Act creates concurrent jurisdiction for federal and state courts over all suits brought to enforce any duty or liability created by the Securities Act or the rules and regulations thereunder. Stockholders may be subject to increased costs to bring these claims, and the choice of forum provisions could have the effect of discouraging claims or limiting investors' ability to bring claims in a judicial forum that they find favorable.

Limitation of Liability and Indemnification Matters

Our amended and restated certificate of incorporation limits the liability of our directors for monetary damages for breach of their fiduciary duty as directors, except for liability that cannot be eliminated under the DGCL. Delaware law provides that directors of a company will not be personally liable for monetary damages for breach of their fiduciary duty as directors, except for liabilities:

Any amendment, repeal or modification of these provisions will be prospective only and would not affect any limitation on liability of a director for acts or omissions that occurred prior to any such amendment, repeal or modification.

Our amended and restated bylaws also provide that we will indemnify our directors and officers to the fullest extent permitted by Delaware law. Our amended and restated bylaws also permit us to purchase insurance on behalf of any officer, director, employee or other agent for any liability arising out of that person's actions as our officer, director, employee or agent, regardless of whether Delaware law would permit indemnification. We have entered into indemnification agreements with each of our current directors and officers and intend to enter into indemnification agreement with any future directors and officers. These agreements require us to indemnify these individuals to the fullest extent permitted under Delaware law against liability that may arise by reason of their service to us, and to advance expenses incurred as a result of any proceeding against them as to which they could be indemnified. We believe that the limitation of liability provision that is in our amended and restated certificate of incorporation and the indemnification agreements will facilitate our ability to continue to attract and retain qualified individuals to serve as directors and officers.

Transfer Agent and Registrar

The transfer agent and registrar for our Class A common stock is Equiniti Trust Company, LLC.

Listing

Our Class A common stock is listed on the NYSE under the symbol "SEI."

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PLAN OF DISTRIBUTION

We may sell securities described in this prospectus and any accompanying prospectus supplement through underwriters, through broker-dealers, in "at the market offerings," within the meaning of Rule 415(a)(4) of the Securities Act to or through a market maker or into an existing trading market on an exchange or otherwise, through agents, on one or more exchanges, directly to one or more purchasers, including existing stockholders, through a combination of any of the foregoing methods of sale, or through any other method permitted by applicable law.

We will prepare a prospectus supplement for each offering that will disclose the terms of the offering, including the name or names of any underwriters, dealers, or agents, the purchase price of the securities and the proceeds to us from the sale, any underwriting discounts, and other items constituting compensation to underwriters, dealers, or agents.

We will fix a price or prices of our securities at:

We may change the price of the securities offered from time to time.

If we use underwriters or dealers in the sale, they will acquire the securities for their own account, and they may resell these securities from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price, or at varying prices determined at the time of sale. The securities may be offered to the public either through underwriting syndicates represented by one or more managing underwriters or directly by one or more of such firms. Unless otherwise disclosed in the prospectus supplement, the obligations of the underwriters to purchase securities will be subject to certain conditions precedent, and the underwriters will be obligated to purchase all of the securities offered by the prospectus supplement if any of the securities are purchased. Any initial public offering price and any discounts or concessions allowed or re-allowed or paid to dealers may be changed from time to time.

We may sell the securities through agents designated by us from time to time. We will name any agent involved in the offering and sale of the securities for which this prospectus is delivered, and disclose any commissions payable by us to the agent or the method by which the commissions can be determined, in the prospectus supplement. Unless otherwise indicated in the prospectus supplement, any agent will be acting on a best efforts basis for the period of its appointment.

Offers to purchase securities may be solicited directly by us and the sale thereof may be made by us directly to institutional investors or others, who may be deemed to be underwriters within the meaning of the Securities Act with respect to any resale thereof. The terms of any such sales will be described in the prospectus supplement relating thereto. We may use electronic media, including the internet, to sell offered securities directly.

We may engage in at-the-market offerings and offer our securities into an existing trading market in accordance with Rule 415(a)(4) under the Securities Act on the terms described in the prospectus supplement relating thereto. Underwriters, dealers, and agents who participate in any at-the-market offerings will be described in the prospectus supplement relating thereto.

We may agree to indemnify underwriters, dealers, and agents who participate in the distribution of securities against certain liabilities to which they may become subject in connection with the sale of the securities, including liabilities arising under the Securities Act.

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Certain of the underwriters and their affiliates may be customers of, may engage in transactions with and may perform services for us or our affiliates in the ordinary course of business.

A prospectus and accompanying prospectus supplement in electronic form may be made available on the websites maintained by the underwriters. The underwriters may agree to allocate a number of securities for sale to their online brokerage account holders. Such allocations of securities for internet distributions will be made on the same basis as other allocations. In addition, securities may be sold by the underwriters to securities dealers who resell securities to online brokerage account holders.

To the extent required, this prospectus may be amended or supplemented from time to time to describe a specific plan of distribution. The place and time of delivery for the securities in respect of which this prospectus is delivered will be set forth in the accompanying prospectus supplement.

In connection with offerings of securities under the registration statement of which this prospectus forms a part and in compliance with applicable law, underwriters, brokers, or dealers may engage in transactions that stabilize or maintain the market price of the securities at levels above those that might otherwise prevail in the open market. Specifically, underwriters, brokers, or dealers may over-allot in connection with offerings, creating a short position in the securities for their own accounts. For the purpose of covering a syndicate short position or stabilizing the price of the securities, the underwriters, brokers, or dealers may place bids for the securities or effect purchases of the securities in the open market. Finally, the underwriters may impose a penalty whereby selling concessions allowed to syndicate members or other brokers or dealers for distribution of the securities in offerings may be reclaimed by the syndicate if the syndicate repurchases previously distributed securities in transactions to cover short positions, in stabilization transactions or otherwise. These activities may stabilize, maintain, or otherwise affect the market price of the securities, which may be higher than the price that might otherwise prevail in the open market, and, if commenced, may be discontinued at any time.

We, the underwriters or other agents may engage in derivative transactions involving the securities. These derivatives may consist of short sale transactions and other hedging activities. The underwriters or agents may acquire a long or short position in the securities, hold or resell securities acquired and purchase options or futures on the securities and other derivative instruments with returns linked to or related to changes in the price of the securities. In order to facilitate these derivative transactions, we may enter into security lending or repurchase agreements with the underwriters or agents. The underwriters or agents may effect the derivative transactions through sales of the securities to the public, including short sales, or by lending the securities in order to facilitate short sale transactions by others. The underwriters or agents may also use the securities purchased or borrowed from us or others (or, in the case of derivatives, securities received from us in settlement of those derivatives) to directly or indirectly settle sales of the securities or close out any related open borrowings of the securities.

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LEGAL MATTERS

The validity of the issuance of the securities offered in this prospectus will be passed upon for us by Vinson & Elkins L.L.P., Houston, Texas. If certain legal matters in connection with an offering of the securities made by this prospectus and a related prospectus supplement are passed upon by counsel for the underwriters of such offering, that counsel will be named in the applicable prospectus supplement related to that offering.

EXPERTS

The consolidated financial statements of Solaris Energy Infrastructure, Inc. as of December 31, 2024 and 2023 and for each of the years then ended and management's assessment of the effectiveness of internal control over financial reporting as of December 31, 2024, incorporated by reference in this prospectus and in the registration statement, have been so incorporated in reliance on the reports of BDO USA, P.C., an independent registered public accounting firm, given on the authority of said firm as experts in auditing and accounting. The report on the effectiveness of internal control over financial reporting contains an explanatory paragraph relating to the exclusion of Mobile Energy Rentals, LLC from the scope of management's assessment of the effectiveness of internal control over financial reporting and our audit of internal control over financial reporting as of December 31, 2024.

The financial statements of Mobile Energy Rentals, LLC as of December 31, 2023 and 2022, and for the year ended December 31, 2023 and the period from February 23, 2022 (inception) to December 31, 2022, incorporated by reference in this prospectus and in the registration statement, have been so incorporated in reliance on the report of BDO USA, P.C., independent auditors, given on the authority of said firm as experts in auditing and accounting. The report on the financial statements contains an explanatory paragraph regarding Mobile Energy Rentals, LLC's ability to continue as a going concern.

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    Shares

Class A Common Stock

PROSPECTUS SUPPLEMENT

    , 2025

Morgan Stanley