As filed with the Securities and Exchange Commission on July 17, 2026

Securities Act File No. 333-[ ]

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, DC 20549

FORM N-14

REGISTRATION STATEMENT

UNDER

COLUMBIA ETF TRUST I

(Exact Name of Registrant as Specified in Charter)

290 Congress Street, Boston, Massachusetts 02210

(Address of Principal Executive Offices) (Zip Code)

Registrant's Telephone Number, Including Area Code: (800) 345-6611

(Name and Address of Agents for Service)

TITLE OF SECURITIES BEING REGISTERED:

Shares of Beneficial Interest, no par value, of Columbia Large Cap Growth ETF, a series of the Registrant.

Approximate Date of Proposed Public Offering: As soon as practicable after the effective date of this Registration Statement.

It is proposed that this filing will become effective on August 17, 2026, pursuant to Rule 488 under the Securities Act of 1933, as amended.

No filing fee is required because an indefinite number of shares have previously been registered pursuant to Rule 24f-2 under the Investment Company Act of 1940.

COLUMBIA FUNDS SERIES TRUST I

Columbia Integrated Large Cap Growth Fund II

290 Congress Street

Boston, MA 02210

1-800-345-6611

www.columbiathreadneedleus.com

August 17, 2026

Dear Shareholder:

I am writing to inform you about a transaction that will affect your investment in Columbia Integrated Large Cap Growth Fund II (the "Target Fund").

You are receiving this combined Information Statement and Prospectus (the "Combined Information Statement/Prospectus") because you own shares in the Target Fund. The Target Fund is a series of Columbia Funds Series Trust I ("CFST I") and is managed by Columbia Management Investment Advisers, LLC ("Columbia Threadneedle"). We are pleased to inform you of the planned merger of the Target Fund, which is a mutual fund, with and into an exchange-traded fund ("ETF"), which is also managed by Columbia Threadneedle. The Funds have substantially the same investment strategies and policies (though the Acquiring Fund is an ETF and the Target Fund is permitted to invest in ETFs) and similar investment restrictions. The Acquiring Fund, like the Target Fund, focuses on equity securities of large capitalization companies.

Pursuant to an Agreement and Plan of Reorganization (the "Agreement"), the Target Fund will be merged with and into Columbia Large Cap Growth ETF (the "Acquiring Fund"), an ETF that is a series of Columbia ETF Trust I, a Massachusetts business trust ("ETF Trust I") (the "Reorganization").

The Agreement, which is by and among CFST I, on behalf of the Target Fund, ETF Trust I, on behalf of the Acquiring Fund, and Columbia Threadneedle (solely with respect to Sections 5.3, 7.3, 10.2 and 12.2), provides for: (i) the acquisition of the assets and assumption of the liabilities and obligations of the Target Fund by the Acquiring Fund in exchange for shares of the Acquiring Fund of equal value to the net assets of the Target Fund being acquired (less the value of any cash delivered to the Target Fund for distribution to Target Fund shareholders (a) in lieu of any fractional shares of the Acquiring Fund that would have otherwise been distributable to such shareholders and (b) to shareholders who do not have a brokerage account to receive Acquiring Fund Shares and instead receive a distribution of cash equal to the net asset value of their Target Fund shares surrendered in the Reorganization ("Cash-Out Shareholders"); (ii) the pro rata distribution of such shares to the shareholders of the Target Fund, with cash distributed (a) in lieu of fractional shares of the Acquiring Fund and (b) to Cash-Out Shareholders; and (iii) the complete liquidation and dissolution of the Target Fund, all upon the terms and conditions set forth in the Agreement. The Agreement has been filed as an exhibit to the Acquiring Fund's Registration Statement on Form N-14 of which the Combined Information Statement/Prospectus is a part.

In connection with the Reorganization, shareholders will receive ETF shares of the Acquiring Fund equal in value to their investment in the Target Fund (less the value of cash to be distributed (a) in lieu of fractional shares of the Acquiring Fund and (b) to Cash-Out Shareholders). As discussed further below, some shareholders may need to take additional action in order to buy and sell shares of the Acquiring Fund received in connection with the Reorganization. However, the Reorganization will not dilute the value of your investment. Cash payments received in lieu of fractional shares of the Acquiring Fund (because the Acquiring Fund does not issue fractional shares, as it trades in whole shares only) or to Cash-Out Shareholders will be taxable for shareholders who hold fractional shares in a taxable account.

After careful consideration, the Board has unanimously approved the Reorganization based on its determination that it is in the best interest of Target Fund shareholders. Expected benefits of the Reorganization include a lower expense ratio for the Acquiring Fund when compared to the gross and net expense ratio of

Class Inst shares of the Target Fund and improved tax efficiency associated with the ETF structure. Class Inst is the oldest and only class of shares currently offered by the Target Fund. The Reorganization is currently expected to occur on or about November 23, 2026, though the Reorganization may be delayed. Shareholder approval of the Reorganization is not required. The Combined Information Statement/Prospectus is for informational purposes only, and you do not need to do anything in response to receiving it except confirm whether you have a brokerage account that can accept shares of an ETF and to consider opening such an account, if you wish to transact in shares of the Acquiring Fund. We are not asking you for a proxy (i.e., for vote instructions), and you are requested not to send a proxy (provide voting instructions). Details regarding the terms of the Reorganization, including its potential benefits and costs to shareholders and information for shareholders who are not currently eligible to hold ETF shares, are discussed in the Combined Information Statement/Prospectus, which we urge you to review carefully. Please read this Combined Information Statement/Prospectus and keep it for future reference.

Sincerely,

Michael G. Clarke, President

Columbia Funds Series Trust I

COLUMBIA FUNDS SERIES TRUST I

Columbia Integrated Large Cap Growth Fund II

COMBINED INFORMATION STATEMENT/PROSPECTUS

August 17, 2026

Columbia Management Investment Advisers, LLC ("Columbia Threadneedle") has recommended, and the Board of Trustees of Columbia Integrated Large Cap Growth Fund II (the "Target Fund") has approved, a proposal to reorganize the Target Fund into Columbia Large Cap Growth ETF (the "Acquiring Fund"). Both the Target Fund and the Acquiring Fund are managed by Columbia Threadneedle. It is proposed that the Target Fund, which is currently operated as a mutual fund, will be converted into an exchange-traded fund ("ETF") through a merger with and into the Acquiring Fund (the "Reorganization"). The Target Fund and Acquiring Fund are referred to collectively as the "Funds." No shareholder approval is required to effect the Reorganization, which is expected to be completed on or about November 23, 2026.

This is a brief overview of the Reorganization of the Target Fund. We encourage you to read the full text of the enclosed combined Information Statement/Prospectus (the "Combined Information Statement/Prospectus") to obtain detailed information with respect to the Reorganization of the Target Fund. This Combined Information Statement/Prospectus was first mailed to shareholders of the Target Fund beginning on or about September 17, 2026.

SHAREHOLDER APPROVAL OF THE REORGANIZATION IS NOT REQUIRED. THIS COMBINED INFORMATION STATEMENT/PROSPECTUS IS FOR INFORMATIONAL PURPOSES ONLY, AND YOU DO NOT NEED TO DO ANYTHING IN RESPONSE TO RECEIVING IT EXCEPT TO CONFIRM WHETHER YOU HAVE A BROKERAGE ACCOUNT THAT CAN ACCEPT SHARES OF AN ETF AND TO CONSIDER OPENING SUCH AN ACCOUNT, IF NEEDED. NO FUND IS ASKING YOU FOR A PROXY OR TO VOTE ON ANYTHING WITH RESPECT TO THE REORGANIZATION AND YOU ARE NOT BEING REQUESTED TO SEND A PROXY OR ANY VOTING INSTRUCTION TO THE FUND WITH RESPECT TO THE REORGANIZATION.

Shareholders of the Target Fund should know the options available to them with respect to the Reorganization, including (i) maintaining current positions in Target Fund shares and receiving shares of the Acquiring Fund ("Acquisition Shares") on the Closing Date (as defined below); (ii) exchanging Target Fund shares for shares of another Columbia Threadneedle mutual fund prior to the Reorganization; and (iii) redeeming Target Fund shares prior to the Reorganization. Target Fund shareholders holding shares in a taxable account should also consider possible tax consequences of (ii) and (iii).

Importantly, in order to buy and sell Acquisition Shares received as a result of the Reorganization, Target Fund shareholders must hold their Target Fund shares through a brokerage account that can hold shares of an ETF. If Target Fund shareholders do not hold their Target Fund shares through a brokerage account that can hold shares of an ETF, their shares will be liquidated, and the proceeds will be sent to the shareholder of record and will be a taxable event.

No further action is required for Target Fund shareholders that hold shares of the Target Fund through a brokerage account that can hold shares of an ETF.

Q: What information is included in the Combined Information Statement/Prospectus?

The enclosed Combined Information Statement/Prospectus provides information about the Reorganization of the Target Fund, and information about the ETF shares that you will receive as a result of the

Reorganization. Although the Combined Information Statement/Prospectus includes information that you should review and keep for future reference, it is not a solicitation of a proxy from you. You are not being asked to vote on any matter in connection with the Reorganization.

Q: What is a fund reorganization?

A fund reorganization involves one target fund transferring all of its assets to an acquiring fund in exchange for shares of such acquiring fund and the assumption by the acquiring fund of all liabilities and obligations of the target fund. Once completed, shareholders of the fund being reorganized (i.e., the target fund) will hold shares of the acquiring fund, and the target fund thereafter is typically dissolved, which will be the case for the Target Fund.

Q: What funds will be involved in the Reorganization?

The Combined Information Statement/Prospectus provides information about the Reorganization of the Target Fund into the Acquiring Fund, as set forth in the table below:

Q: What actions do I need to take in connection with the Reorganization?

None - unless you hold Target Fund shares in an account that cannot transact in ETF shares. In order to buy and sell the shares of the Acquiring Fund you receive in the Reorganization, you would need to hold such shares in a brokerage account that can transact in ETF shares.

In accordance with the Target Fund's Agreement and Declaration of Trust and applicable state and U.S. federal law (including Rule 17a-8 under the Investment Company Act of 1940, as amended (the "1940 Act")), the Reorganization may be effected without the approval of shareholders of the Target Fund. Your Target Fund shares will automatically be converted into shares of the Acquiring Fund on the Closing Date of the Reorganization of the Target Fund with and into the Acquiring Fund. You will receive written confirmation that this change has taken place. No certificates for shares will be issued in connection with the Reorganization. The aggregate net asset value (the "NAV") of the Acquisition Shares you receive in the Reorganization will be equal to the aggregate NAV of the shares you own in the Target Fund computed as of the close of regular trading on the New York Stock Exchange on the Valuation Date (as defined below) less cash you receive (a) in lieu of fractional Acquisition Shares or (b) because you do not have a brokerage account to receive Acquiring Fund Shares and will instead receive a distribution of cash equal to the net asset value of your Target Fund shares surrendered in the Reorganization (referred to herein as a "Cash-Out Shareholder"). If you sell your shares or are otherwise no longer a shareholder of the Target Fund as of the Closing Date of the Reorganization, this transaction will not impact you. Class Inst is the oldest and only class of shares currently offered by the Target Fund.

It is important for you to determine whether you hold your Target Fund shares in the type of account that can accommodate the ETF shares that will be received in the Reorganization. If you hold your shares of the Target Fund in an account directly with the Target Fund at the Target Fund's transfer agent or in a brokerage account with a financial intermediary that only allows you to hold mutual fund shares, you will need to set up a brokerage account that allows investments in ETF shares if the Reorganization is consummated and you wish to transact in shares of the Acquiring Fund.

In order to buy and sell Acquisition Shares received as a result of the Reorganization, you must hold your Target Fund shares through a brokerage account that can hold shares of an ETF. If you do not hold your Target Fund shares through a brokerage account that can hold shares of an ETF, your shares will be liquidated, and the proceeds will be sent to the shareholder of record and will be a taxable event.

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No further action is required for Target Fund shareholders that hold shares of the Target Fund through a brokerage account that can hold shares of an ETF.

For more information see the section of the enclosed Combined Information Statement/Prospectus titled "Section A - The Reorganization - Summary - Important Information for Target Fund Shareholders."

Q: Why did Columbia Threadneedle propose the Reorganization?

Columbia Threadneedle, the investment manager for the Target Fund and Acquiring Fund, has recommended the Reorganization because it believes that the Reorganization is in the best interests of shareholders of the Target Fund and the Acquiring Fund. Columbia Threadneedle believes that reorganizing the Target Fund into the Acquiring Fund and the resulting conversion into an ETF may offer operational advantages, including lower overall operating expenses, potentially more efficient portfolio management, and more flexible trading of shares of the Acquiring Fund (i.e., the ability of shareholders to buy or sell shares at current market prices throughout the trading hours of NYSE Arca, Inc. ("NYSE Arca" or the "Exchange"), the exchange upon which shares of the Acquiring Fund are listed and traded). Further, management believes that, absent the Reorganization, the Target Fund, is unlikely to achieve long-term economic viability. For more information, please see "What are some features of ETFs that differ from mutual funds?" below. Following the Reorganization, shareholders of the Target Fund would be invested in a fund with a lower net annual fund operating expense ratio. Please refer to "Section A - The Reorganization - Summary - Fees and Expenses" and "Section A - The Reorganization - Synopsis - Comparison of Management of the Funds" in the enclosed Combined Information Statement/Prospectus for a detailed discussion of the Reorganization's expected impact on management fee rates and total and net annual fund operating expense ratios. The Acquiring Fund, like the Target Fund, seeks capital appreciation as its investment objective. Each Fund focuses on equity securities of large capitalization companies and uses the Russell 1000^® Growth Index as its primary performance benchmark. The Funds have substantially the same investment strategies and policies (though the Acquiring Fund is an ETF and the Target Fund is permitted to invest in ETFs) and similar investment restrictions. Please see "The Reorganization - Synopsis - Comparison of Investment Objectives, Principal Investment Strategies and Non-Fundamental Investment Policies" in the enclosed "Combined Information Statement/Prospectus" for a detailed comparison of the investment objective, principal investment strategies and risks of the two Funds.

Q: What will happen if the Reorganization occurs?

If the closing conditions of the Reorganization under the Agreement are satisfied or waived, then shareholders of the Target Fund will become shareholders of the Acquiring Fund on or about November 23, 2026 (the "Closing Date") and will no longer be shareholders of the Target Fund. Shareholders of the Target Fund will receive shares of the Acquiring Fund with an equivalent aggregate NAV of their shares of the Target Fund (less the value of cash to be distributed in lieu of fractional Acquisition Shares and to Cash-Out Shareholders).

In particular, the Agreement provides that (1) the assets of the Target Fund will be acquired by the Acquiring Fund and the liabilities and obligations of the Target Fund will be assumed by the Acquiring Fund in exchange for Acquisition Shares of equal value to the net assets attributable to shares of the Target Fund being acquired, with cash to be delivered to the Target Fund (a) in lieu of fractional Acquisition Shares that would otherwise be distributed to shareholders of the Target Fund and (b) to Cash-Out Shareholders; and (2) the Acquisition Shares received by the Target Fund in the exchange will then be distributed pro rata to shareholders of the Target Fund, with the cash equivalent to the value of (i) any fractional Acquisition Shares due to shareholders being delivered to such shareholders and (ii) the Target Fund shares surrendered in the Reorganization by Cash-Out Shareholders being delivered to such shareholders. After the Acquisition Shares and cash are distributed to the Target Fund's shareholders, the Target Fund will be liquidated.

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Q: What are some features of ETFs that differ from mutual funds?

The following are some unique features of ETFs that differ from mutual funds:

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In addition, the Acquiring Fund is subject to certain risks unique to operating as an ETF. For more information, see "Section A - The Reorganization - Synopsis - Comparison of Principal Risks" in the enclosed "Combined Information Statement/Prospectus."

Q: Has the Target Fund's Board approved the Reorganization?

Yes, the Board of Trustees of Columbia Funds Series Trust I ("CFST I") (the "Board") has approved the Reorganization because it believes that it is in the best interests of the Target Fund. At a meeting held in June 2026, the Board carefully reviewed the terms of the Reorganization and unanimously approved the Agreement. For the reasons set forth in the "Board Considerations" section of this Combined Information Statement/Prospectus, the Board, including the Trustees who are not "interested persons" as defined in the 1940 Act, of CFST I has determined that participation in the Reorganization is in the best interests of the Target Fund. The Board also concluded that no dilution in value would result to the shareholders of the Target Fund as a result of the Reorganization. 

Q: How will the Reorganization affect me as a shareholder?

If the Reorganization is completed, you will cease to be a shareholder of the Target Fund and will become a shareholder of the Acquiring Fund. Upon completion of the Reorganization, Target Fund shareholders will own shares of the Acquiring Fund, which is an ETF, having an aggregate NAV equal to the aggregate NAV of shares of the Target Fund that were owned when the Reorganization happened (less the value of any cash delivered (a) in lieu of fractional Acquisition Shares that would otherwise be distributed to shareholders of the Target Fund and (b) to Cash-Out Shareholders). Shares of the Acquiring Fund will be transferred to a shareholder's brokerage account.

Importantly, in order to buy and sell Acquisition Shares received as a result of the Reorganization, you must hold your Target Fund shares through a brokerage account that can hold shares of an ETF. If you do not hold your Target Fund shares through a brokerage account that can hold shares of an ETF, your shares will be liquidated, and the proceeds will be sent to the shareholder of record, which will be a taxable event. Different consequences may apply to tax-advantaged accounts, including IRAs and retirement plans.

No further action is required for Target Fund shareholders that hold shares of the Target Fund through a brokerage account that can hold shares of an ETF.

For more information about the brokerage account needed to hold shares of the Acquiring Fund, see "Section A - The Reorganization - Summary - Important Information for Target Fund Shareholders" in the enclosed Combined Information Statement/Prospectus.

Shares of the Acquiring Fund are not issued in fractional shares. As a result, the Target Fund shareholders will receive cash equivalent to the value of any fractional Acquisition Shares due to such shareholders, which will be a taxable redemption of shares for shareholders who hold fractional shares in a taxable account. Shareholders should consult their tax advisors to determine the effect of the redemption of fractional Acquisition Shares.

After the Reorganization, individual shares of the Acquiring Fund may only be purchased and sold on the NYSE Arca, other national securities exchanges, electronic crossing networks and other alternative trading

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systems. Should a former Target Fund shareholder decide to purchase or sell shares in the Acquiring Fund after the Reorganization, the shareholder will need to place a trade through a financial intermediary, such as a broker, who will execute the trade on an exchange at prevailing market prices. Because shares of the Acquiring Fund trade at market prices rather than at NAV per share, the Acquiring Fund shares may trade at a price less than (discount) or greater than (premium) the then-current net asset value per share of the Acquiring Fund. As with all ETFs, your financial intermediary may charge a commission or other transaction fee for purchase and sale transactions in ETF shares, although ETFs trade with NTF on many platforms. In addition, it is ETF Trust I's understanding that the brokerage account statements that Acquiring Fund shareholders will receive from financial intermediaries following the Reorganization will provide information on the market price of the Acquiring Fund's shares and not the NAV per share of the Acquiring Fund as would be the case for a mutual fund. Unlike the Target Fund, the Acquiring Fund does not offer exchange privileges.

Q: Will the portfolio managers of my fund change as a result of the Reorganization?

No. Columbia Threadneedle is also the investment manager for the Acquiring Fund and the portfolio managers of the Acquiring Fund are the same as the portfolio managers for the Target Fund. Columbia Threadneedle portfolio managers of the Acquiring Fund are expected to continue to manage the Acquiring Fund following the Reorganization.

Q: Who will bear the expenses of the Reorganization?

You will not pay any sales charges in connection with receiving Acquisition Shares issued in the Reorganization. Under the Agreement, the Target Fund expenses of the Reorganization are expected to be shared by the Target Fund and Columbia Threadneedle. The Target Fund will bear expenses of the Reorganization to the extent that such expenses (other than costs of repositioning the Target Fund's portfolio) do not exceed the anticipated reduction in expenses that shareholders of the Target Fund will realize in the first year following the Reorganization. Any amounts in excess of this limit will be borne by Columbia Threadneedle. If the Reorganization does not occur, Columbia Threadneedle will bear all expenses associated with the Reorganization.

Q: Will there be any costs associated with portfolio repositioning?

Yes, but they are expected to be minimal, if any, because there is significant portfolio overlap between the Target Fund and the Acquiring Fund. If the Reorganization had occurred as of March 31, 2026, it is estimated that approximately 3% of the Target Fund's investment portfolio would have been sold by the Acquiring Fund and any transaction costs borne by the Acquiring Fund would be de minimis. The actual transaction costs will vary based on the degree of portfolio overlap between the Target Fund and the Acquiring Fund at the time of the Reorganization and on market conditions at the time of sale, if any. See the section of the enclosed Combined Information Statement/Prospectus titled "Section A - The Reorganization - Summary - Fees and Expenses" for additional information regarding the Target Fund's portfolio repositioning.

Q: What are the U.S. federal income tax consequences of the Reorganization?

The Reorganization is expected to constitute a "reorganization" within the meaning of Section 368(a) of the Internal Revenue Code of 1986, as amended, (the "Code") and generally is not expected to result in recognition of gain or loss by the Target Fund or its shareholders. However, shareholders who hold fractional shares of the Target Fund will receive cash compensation in lieu of fractional Acquisition Shares (because ETFs do not offer or make available fractional shares). Such shareholders will generally be required to recognize gain or loss upon the receipt of cash. In addition, Cash-Out Shareholders who hold their Target Fund shares in a brokerage account that cannot hold shares of an ETF and who do not establish a brokerage account that can hold shares of an ETF will receive a cash payment in liquidation of the Acquisition Shares they are entitled to receive as part of the Reorganization. Such shareholders will generally be required to recognize gain or loss upon the

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receipt of cash for their Target Fund shares, based on such shareholder's adjusted tax basis in his or her Target Fund shares. The Target Fund may be required to sell securities in order to fund such share liquidations, which may result in the recognition of gains that are distributed to shareholders of the Target Fund as taxable dividends.

Prior to the Reorganization, the Target Fund will declare a distribution to shareholders that, together with all previous distributions qualifying for the dividends-paid deduction, will have the effect of distributing to shareholders, all of its investment company taxable income, net tax-exempt income (if any), and net capital gains, including those realized on the disposition of portfolio securities, whether independent of or in connection with the Reorganization, effected prior to the Reorganization. This distribution will generally be taxable to shareholders.

As a condition of the closing of the Reorganization and assuming the parties comply with the terms of the Agreement and CFST I, on behalf of the Target Fund, and ETF Trust I, on behalf of the Acquiring Fund, will receive an opinion of counsel regarding the federal income tax consequences of the Reorganization. Shareholders should consult their tax advisers about state and local tax consequences of the Reorganization, if any, because the information about tax consequences in this Combined Information Statement/Prospectus relates only to the federal income tax consequences of the Reorganization.

For more information see the section of the enclosed Combined Information Statement/Prospectus entitled "Section A-The Reorganization - Additional Information About the Reorganization - U.S. Federal Income Tax Status of the Reorganization."

Q: Will there be any changes to my fees and expenses as a result of the Reorganization?

Yes. Following the Reorganization, the total and net annual fund operating expenses of the Acquiring Fund are expected to be lower than those of Class Inst of the Target Fund, which is the Target Fund's only share class. The Acquiring Fund employs a unitary fee structure pursuant to which Columbia Threadneedle bears substantially all operating expenses of the Acquiring Fund, subject to certain exceptions. The contractual (unitary) management fee rate for the Acquiring Fund is lower than the contractual management fee rate of the Target Fund at all breakpoints. For a more detailed discussion of the Funds' fees and expenses, see the section of the enclosed Combined Information Statement/Prospectus titled "Section A - The Reorganization - Summary - Fees and Expenses."

Q: What types of accounts cannot transact in shares of the Acquiring Fund received as part of the Reorganization?

The following account types generally cannot transact in shares of ETFs:

If you hold your Target Fund shares through a fund direct account and do not take action prior to the Reorganization, your shares will be liquidated, and the proceeds will be sent to the shareholder of record, which will be a taxable event. Different consequences may apply to tax-advantaged accounts. Shareholders holding shares of the Target Fund in these accounts who do not take action to either sell their shares or exchange their shares out of the Target Fund by November 19, 2026, will have such shares liquidated and the proceeds automatically sent to the shareholder of record.

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Q: How do I transfer my Target Fund shares from a non-accommodating brokerage account to a brokerage account that will accept Acquiring Fund shares?

The financial intermediary, such as a broker or dealer, where you hold your Target Fund shares should be able to assist you in changing your account to an account that is permitted to hold ETF shares. Contact your broker right away to make the necessary changes to your account.

Q: What will happen if I don't have a brokerage account that can hold ETF shares at the time of the Reorganization?

In order to buy and sell Acquisition Shares received as a result of the Reorganization, you must hold your Target Fund shares through a brokerage account that can hold shares of an ETF. If you do not hold your Target Fund shares through a brokerage account that can hold shares of an ETF, your shares will be liquidated, and the proceeds will be sent to the shareholder of record, which will be a taxable event. Different consequences may apply to tax-advantaged accounts, including IRAs and retirement plans.

Q: What if I don't want to hold ETF shares?

If you do not want to receive ETF shares in connection with the Reorganization, you may redeem your shares of the Target Fund or you may exchange those shares for shares of another eligible mutual fund managed by Columbia Threadneedle until November 19, 2026. If a Target Fund shareholder redeems his or her shares and such shares are held in a taxable account, the shareholder will recognize a taxable gain or loss based on the difference between the redeeming shareholder's tax basis in the shares and the amount that the redeeming shareholder receives for them. Shareholders of the Target Fund may exchange their Target Fund shares for shares of the same class of any mutual fund, other than the Target Fund, that is managed by Columbia Threadneedle, as applicable, generally without paying any additional sales charges, provided that the fund shares to be acquired in the exchange are available to new investors in such other fund and the shareholder is eligible to invest in such shares. Please see the prospectus for such other Columbia mutual funds (which are not part of this Combined Information Statement/Prospectus). Such an exchange of shares for shares in another fund will generally result in the recognition of taxable gain or loss for shareholders holding shares in a taxable account. As an ETF, the Acquiring Fund does not provide for the exchange of shares.

Q: What is the anticipated timing of the Reorganization?

The Reorganization is currently expected to be completed on or about November 23, 2026.

Q: Can I purchase, redeem or exchange Target Fund shares before the Reorganization takes place?

Yes. You can purchase Target Fund shares until November 18, 2026. The Target Fund will accept requests for redemptions or exchanges only if received in proper form before the close of trading on the New York Stock Exchange ("NYSE") (usually 4:00 p.m. Eastern time or the time trading closes on the NYSE, whichever is earlier), on November 19, 2026. Any shares not redeemed or exchanged before such time will be exchanged for Acquisition Shares on the Closing Date; and, after such time, Target Fund shareholders wishing to sell their Acquisition Shares must do so on an exchange using their brokerage account.

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Q: Whom should I call if I have questions?

If you have questions about any of the Reorganization described in the Combined Information Statement/Prospectus, please call 800-345-6611.

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The information contained in this Combined Information Statement/Prospectus is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This Combined Information Statement/Prospectus is not an offer to sell these securities, and it is not soliciting an offer to buy these securities, in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED JULY 17, 2026

COLUMBIA FUNDS SERIES TRUST I

Columbia Integrated Large Cap Growth Fund II

COMBINED INFORMATION STATEMENT/PROSPECTUS

Dated August 17, 2026

Introduction

This combined Information Statement and Prospectus (the "Combined Information Statement/Prospectus") is an information statement for the Target Fund (as defined below) and a prospectus for the Acquiring Fund (as defined below). The Combined Information Statement/Prospectus relates to the merger of the Target Fund with and into the Acquiring Fund (the "Reorganization"). The table below sets forth the Target Fund and the Acquiring Fund for the Reorganization.

The address of the Target Fund and Acquiring Fund is 290 Congress Street, Boston, MA 02210. The telephone number for the Target Fund is (800) 345-6611 and the telephone number for the Acquiring Fund is (800) 426-3750. This Combined Information Statement/Prospectus was first mailed to shareholders of the Target Fund beginning on or about September 17, 2026. This Combined Information Statement/Prospectus explains what you should know about the Reorganization and investing in your Acquiring Fund. You should read this document carefully and retain it for future reference.

THIS COMBINED INFORMATION STATEMENT/PROSPECTUS IS FOR INFORMATION PURPOSES ONLY, AND YOU DO NOT NEED TO DO ANYTHING IN RESPONSE TO RECEIVING IT EXCEPT TO CHECK WHETHER YOU HAVE A BROKERAGE ACCOUNT THAT CAN ACCEPT SHARES OF AN EXCHANGE-TRADED FUND ("ETF") AND CONSIDER OPENING SUCH AN ACCOUNT, IF NEEDED. NO FUND IS ASKING YOU FOR A PROXY OR TO VOTE ON ANYTHING WITH RESPECT TO THE REORGANIZATION AND YOU ARE NOT BEING REQUESTED TO SEND US A PROXY OR ANY VOTING INSTRUCTION WITH RESPECT TO THE REORGANIZATION.

The terms and conditions of the Reorganization are further described in this Combined Information Statement/Prospectus and are set forth in the form of Agreement and Plan of Reorganization (the "Agreement").

The Boards of Trustees of Columbia Funds Series Trust I ("CFST I") and Columbia ETF Trust I ("ETF Trust I") (together, the "Board") unanimously approved the proposed Reorganization and Agreement. The Board of CFST I determined that participation in the Reorganization is in the best interests of the Target Fund and that the interests of existing Target Fund shareholders will not be diluted as a result of the Reorganization. In addition, the Board of ETF Trust I approved the proposed Reorganization and determined it is in the best interests of the Acquiring Fund.

The Reorganization is anticipated to close on or around November 23, 2026 (the "Closing Date"). The Closing Date may be delayed. The Target Fund intends to publicly disclose any changes to the Closing Date. In preparation for the closing of the Reorganization, purchase orders must be received by the Target Fund by

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November 18, 2026. The Target Fund will accept requests for redemptions or exchanges only if received in proper form before the close of trading on the New York Stock Exchange ("NYSE") (usually 4:00 p.m. Eastern time or the time trading closes on the NYSE, whichever is earlier), on November 19, 2026,

Each of the Target Fund and the Acquiring Fund is a series of a registered, open-end management investment company, although the Target Fund is a mutual fund while the Acquiring Fund is an ETF. The Acquiring Fund will be the accounting and performance survivor in the Reorganization.

Importantly, in order to buy and sell Acquisition Shares received as a result of the Reorganization, Target Fund shareholders must hold their Target Fund shares through a brokerage account that can hold shares of an ETF. If Target Fund shareholders do not hold their Target Fund shares through a brokerage account that can hold shares of an ETF, their shares will be liquidated, and the proceeds will be sent to the shareholder of record and will be a taxable event. This Combined Information Statement/Prospectus includes additional information on the actions that Target Fund shareholders must take in order to transact in shares of the Acquiring Fund as part of the Reorganization if they do not currently hold their Target Fund shares through a brokerage account that can hold ETF shares.

This Combined Information Statement/Prospectus also includes information about the Agreement and the Acquiring Fund. You should retain this Combined Information Statement/Prospectus for future reference. Additional information about the Target Fund, the Acquiring Fund and the proposed transaction has been filed with the U.S. Securities and Exchange Commission ("SEC") and can be found in the following documents, which are incorporated into this Combined Information Statement/Prospectus by reference:

You may request a free copy of the statement of additional information relating to this Combined Information Statement/Prospectus or the Target Fund's Prospectus without charge by calling Columbia Funds at (800) 345-6611 or by writing to Columbia Management Investment Services Corp., P.O. Box 219104, Kansas City, MO 64121.

To obtain a free copy of the Acquiring Fund's prospectus or to request other information about the Acquiring Fund, please contact the Acquiring Fund by calling Columbia Funds at (800) 426-3750, by writing to Columbia Funds at 290 Congress Street, Boston, MA 02210, or online at columbiathreadneedleus.com/etfs.

Please note that investments in the Funds are not bank deposits, are not federally insured, are not guaranteed by any bank or government agency and may lose value. There is no assurance that any Fund will achieve its investment objectives.

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THE U.S. SECURITIES AND EXCHANGE COMMISSION HAS NOT APPROVED OR DISAPPROVED THESE SECURITIES OR PASSED UPON THE ADEQUACY OR ACCURACY OF THIS COMBINED INFORMATION STATEMENT/PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A CRIMINAL OFFENSE.

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TABLE OF CONTENTS

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SECTION A - THE REORGANIZATION

The following information describes the proposed merger of the Target Fund into the Acquiring Fund (the "Reorganization"). The Target Fund and the Acquiring Fund are referred to collectively as the "Funds." You should read the more complete information in the rest of this Combined Information Statement/Prospectus, including the Acquiring Fund's Prospectus and the Agreement (which has been filed as an exhibit to the Acquiring Fund's Registration Statement on Form N-14 of which this Combined Information Statement/Prospectus is a part).

SUMMARY

Columbia Management Investment Advisers, LLC ("Columbia Threadneedle" or the "Investment Manager") has recommended the Reorganization of the Target Fund with and into the Acquiring Fund. The Board has approved the Reorganization, with an anticipated close on or about November 23, 2026.

This Combined Information Statement/Prospectus provides information about the Reorganization of the Target Fund with and into the Acquiring Fund. The following is only a summary of certain information contained in this Combined Information Statement/Prospectus. More complete information appears later in this Combined Information Statement/Prospectus. You should carefully read the entire Combined Information Statement/ Prospectus and the exhibits because they contain details that are not included in this summary.

How The Reorganization Will Work. The following provides an overview of how the Reorganization will work.

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Did the Board approve the Reorganization? The Board, including all of the trustees who are not "interested persons" (as defined in the 1940 Act) (the "Independent Trustees"), after careful consideration, have determined that the Reorganization is in the best interests of the Target Fund and will not dilute the interests of the existing shareholders of the Target Fund. The Board made this determination based on various factors that are discussed in this Combined Information Statement/Prospectus, under the discussion of the Reorganization in "Section A - The Reorganization - Additional Information About the Reorganization - Board Considerations."

Important Information for Target Fund Shareholders. It is important for you to determine whether you hold your shares of the Target Fund in the type of account that can accommodate the ETF shares you would receive through the Target Fund's Reorganization. If you hold your shares of the Target Fund in an account directly with the Target Fund at the Target Fund's transfer agent or in a brokerage account with a financial intermediary that only allows you to hold mutual fund shares, you will need to set up a brokerage account that allows investments in ETF shares if the applicable Reorganization is consummated and you wish to transact in shares of the Acquiring Fund.

If you do not hold your Target Fund shares through a brokerage account that can hold shares of an ETF, your shares will be liquidated, and the proceeds will be sent to the shareholder of record, which will be a taxable event.

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You should provide your broker with a copy of the quarterly statement from the Target Fund. The broker will require your account number with the Target Fund, which can be found on your statement. The broker will help you complete a form to initiate the transfer. Once you properly complete and sign that form, the broker will submit the form to the Target Fund's transfer agent directly, and the Target Fund shares will be transferred into your brokerage account.

If you do not want to receive ETF shares in connection with the Reorganization, you may redeem your shares of the Target Fund or you may exchange those shares for shares of another eligible mutual fund managed by Columbia Threadneedle until November 19, 2026. If a Target Fund shareholder redeems his or her shares and such shares are held in a taxable account, the shareholder will recognize a taxable gain or loss based on the difference between the redeeming shareholder's tax basis in the shares and the amount that the redeeming shareholder receives for them. Shareholders of the Target Fund may exchange their Target Fund shares for shares of the same class of any mutual fund, other than the Target Fund, that is managed by Columbia Threadneedle, generally without paying any additional sales charges, provided that the fund shares to be acquired in the exchange are available to new investors in such other fund and the shareholder is eligible to invest in such shares. Such an exchange of shares for shares in another fund will generally result in the recognition of taxable gain or loss for shareholders holding shares in a taxable account. As an ETF, the Acquiring Fund does not provide for the exchange of shares.

Omnibus retirement plan recordkeepers may not be able to include ETF shares on their platforms, and in such a case a retirement plan investor may be required by its retirement plan recordkeeper to redeem the Target Fund's shares prior to its Reorganization.

You can contact your financial advisor or other financial intermediary for further information. You also may contact Columbia Management Investment Services Corp. at (800) 345-6611.

U.S. Federal Income Tax Consequences of the Reorganization. The Reorganization is expected to qualify as a tax-free reorganization for U.S. federal income tax purposes and will not take place unless the Target Fund and the Acquiring Fund involved in the Reorganization receive a satisfactory opinion of tax counsel substantially to the effect that the Reorganization will qualify as a tax-free reorganization for U.S. federal income tax purposes, as described in more detail in the section entitled "Section A - The Reorganization -Additional Information About the Reorganization - U.S. Federal Income Tax Status of the Reorganization." Accordingly, subject to the limited exceptions described in that section and below, no gain or loss is expected to be recognized by the Target Fund or its shareholders as a direct result of the Reorganization. However, as part of the Reorganization, shareholders that will receive cash equivalent to the value of Acquisition Shares due to such shareholder (a) in lieu of fractional Acquisition Shares and (b) as Cash-Out Shareholders. Shareholders will generally be required to recognize gain or loss upon the receipt of cash for their fractional Acquisition Shares if they hold fractional shares in a taxable account. Cash-Out Shareholders who hold their Target Fund shares in a brokerage account that cannot hold shares of an ETF will receive a cash payment in liquidation of the Acquiring Fund shares they are entitled to receive as part of the Reorganization. Such shareholders will generally be required to recognize gain or loss upon the receipt of cash for their shares. The Target Fund may be required to sell securities in order to fund such share liquidations, which may result in the recognition of gains that are

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distributed to shareholders of the Target Fund as taxable dividends. A portion of the portfolio assets of the Target Fund is expected to be sold by the Target Fund prior to its Reorganization. Any disposition of portfolio holdings would result in brokerage commissions and other transaction costs, and may result in the realization of capital gains that would be distributed to shareholders during or with respect to the year of sale, and such distributions would be taxable to shareholders unless shares are held through a qualified retirement plan or other tax-advantaged arrangement. Prior to the closing of the Reorganization, the Target Fund will declare and pay a distribution to shareholders, which, together with all previous distributions, will have the effect of distributing to shareholders all of its investment company taxable income, net tax-exempt income, if any, and net realized capital gains, if any, through the closing of the Reorganization, and may include undistributed income or gains from prior years. These distributions will generally be taxable to shareholders that hold their shares in a taxable account. Such distributions may include distributions taxable as ordinary income or as long-term capital gains. A Target Fund shareholder's aggregate tax basis in the Acquisition Shares received is expected to carry over from the shareholder's Target Fund shares, and a Target Fund shareholder's holding period in the Acquisition Shares is expected to include the shareholder's holding period in the Target Fund shares.

For more information about the U.S. federal income tax consequences of the Reorganization, see the section entitled "Section A - The Reorganization - Additional Information About the Reorganization - U.S. Federal Income Tax Status of the Reorganization." For more information regarding repositioning costs, see the section "Section A - The Reorganization - Summary - Fees and Expenses - Portfolio Turnover" below.

Comparison of Fund investment goals, investment strategies and policies, and principal risks. The Acquiring Fund, like the Target Fund, seeks capital appreciation as its investment objective. Each Fund focuses on equity securities of large capitalization companies and uses the Russell 1000^® Growth Index as its primary performance benchmark. The Funds have substantially the same investment strategies and policies (though the Acquiring Fund is an ETF and the Target Fund is permitted to invest in ETFs) and similar investment restrictions. Columbia Threadneedle is the investment manager for the Target Fund and the Acquiring Fund. For information on the comparison of the principal investment objectives, investment policies and principal risks, please see "The Reorganization - Synopsis - Comparison of Investment Objectives, Principal Investment Strategies and Non-Fundamental Investment Policies" in this Combined Information Statement/Prospectus. The portfolio managers of the Acquiring Fund are the same as the portfolio managers for the Target Fund. Columbia Threadneedle portfolio managers of the Acquiring Fund are expected to continue to manage the Acquiring Fund following the Reorganization. Information about the portfolio managers of the Acquiring Fund is included in the section of this Combined Information Statement/Prospectus entitled "Section B - Additional Information Applicable to the Acquiring Fund."

The Target Fund and the Acquiring Fund are subject to many of the same principal risks, but such risks differ primarily due to the Acquiring Fund's structure as an ETF. For additional information on the principal risks of the Target Fund and the Acquiring Fund, please see the sections titled "Comparison of Principal Risks" in the synopsis of the Reorganization in "Section A - The Reorganization" and "Section B - Additional Information About the Acquiring Fund - Principal Risks of the Acquiring Fund."

Fees and Expenses. The following tables describe the fees and expenses that you may pay if you buy, hold and sell shares of a Fund. Following the Reorganization, the total annual fund operating expenses of the Acquiring Fund are expected to be lower than those of the Target Fund. You may pay other fees, such as brokerage commissions and other fees to financial intermediaries, which are not reflected in the tables and examples below. The tables enable you to compare and contrast the expense levels for the Target Fund and the Acquiring Fund, and obtain a general idea of what the expense levels will be if the Reorganization occurs.

Annual fund operating expenses shown in the tables below are based on expenses for the fiscal year ended March 31, 2026 for each of the Target Fund and the Acquiring Fund.

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Also shown are annual fund operating expenses projected for the Acquiring Fund on a pro forma basis after giving effect to the proposed Reorganization, assuming the Reorganization occurred on March 31, 2026. The fee tables do not reflect the expenses associated with the Reorganization.

In comparing the fees and expenses of the Target Fund and the Acquiring Fund, you may wish to consider differences in fee structure. The Target Fund pays Columbia Threadneedle a fee for its management services, which include investment advisory services and administrative services. The management fee paid by the Target Fund to Columbia Threadneedle incorporates asset-level breakpoints, is calculated as a percentage of the daily net assets of the Target Fund and is paid monthly. This fee is separate and apart from the other operating fees/expenses to which the Target Fund is subject. In contrast, the Acquiring Fund pays an all-inclusive management fee to Columbia Threadneedle calculated as a percentage of the daily net assets of the Acquiring Fund and paid monthly. In return for this fee paid by the Acquiring Fund (which is sometimes referred to as a unitary or unified fee), Columbia Threadneedle has agreed to pay the operating costs and expenses of the Acquiring Fund other than the following expenses, which will be paid by the Acquiring Fund: taxes, interest incurred on borrowing by the Acquiring Fund, if any, brokerage fees and commissions, interest and fee expense related to the Acquiring Fund's participation in inverse floater structures and any other portfolio transaction expenses, infrequent and/or unusual expenses, including without limitation litigation expenses, expenses incurred in connection with lending securities, and any other expenses approved by the Board.

Actual fees and expenses of the combined Fund will be based on the Fund's asset levels following the Reorganization. The assets of the Funds will vary based on market conditions, redemptions and other factors.

Shareholder Fees (fees paid directly from your investment)

Annual Fund Operating Expenses (expenses that you pay each year as a percentage of the value of your investment)

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Expense Examples. These examples are intended to help you compare the cost of investing in shares of the Target Fund with the cost of investing in the Acquiring Fund on a pro forma basis, and allow you to compare these costs with the cost of investing in other funds. These examples assume that you invest $10,000 in the applicable Fund for the time periods indicated, whether you redeem all of your shares at the end of those periods or not. These examples also assume that your investment has a 5% return each year and that each Fund's operating expenses remain the same. These examples include any contractual fee waiver/expense reimbursement arrangement only for the period indicated in the Annual Fund Operating Expenses table above. Although your actual costs may be higher or lower, based on those assumptions, your costs would be (whether or not shares are redeemed):

Portfolio Turnover. Each Fund pays transaction costs, such as commissions, when it buys and sells securities (or "turns over" its portfolio). A higher portfolio turnover rate may indicate higher transaction costs and may result in a greater amount of taxes when Fund shares are held in a taxable account. Those costs, which are not reflected in the Annual Fund Operating Expenses table or in the expense examples, affect a Fund's performance. During each Fund's most recent fiscal year, its portfolio turnover rate was the following percentage of the average value of the Fund's portfolio:

A portion of the Target Fund's portfolio assets is expected to be sold by the Target Fund prior to the Reorganization. If the Reorganization had occurred as of March 31, 2026, it is estimated that approximately 3% of the Target Fund's investment portfolio would have been sold by the Acquiring Fund and any transaction costs borne by the Acquiring Fund would be de minimis. If such repositioning had occurred as of March 31, 2026, the Target Fund would have realized net capital gains of approximately $0.6 million on an aggregate basis and $0.14 on a per share basis.

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Comparison of Acquiring Fund and Target Fund Service Providers. The following provides a comparison of the service providers for the Funds.

Comparison of Target Fund and Acquiring Fund Sales Charges and Distribution Arrangements. Shares of the Target Fund do not impose a front-end sales load or contingent deferred sales load. Shares of the Acquiring Fund also are not subject to a front-end sales load or contingent deferred sales charge. However, investors in the Acquiring Fund may incur transaction fees, including but not limited to, brokerage charges in connection with transacting (purchasing and selling) Acquiring Fund shares which list and trade on a stock exchange.

Comparison of Target Fund and Acquiring Fund Purchase and Redemption Provisions. Shares of the Target Fund may be purchased or sold on any day the NYSE is open for business. Shares of the Target Fund do not have investment minimums for certain eligible investors, but have an investment minimum of $2,000 ($1,000 for IRAs and $100 for monthly Systematic Investment Plan accounts) for certain commissionable brokerage platforms (as set forth in the Target Fund's Prospectus) and $1 million for all other eligible investors not specifically referenced in the Target Fund's Prospectus, unless otherwise waived. In certain instances, the

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investment minimums may be waived in the Target Fund's discretion. The Target Fund may be purchased by phone, by mail, online or by wire transaction. For more information, see the "Buying, Selling and Exchanging Shares" section of the Target Fund's Prospectus.

The Acquiring Fund issues and redeems shares only through Authorized Participants (intermediaries, typically broker-dealers who have executed an agreement with the Acquiring Fund's distributor that governs transactions in Acquiring Fund creation units) in large blocks of shares, (typically 50,000 shares, in the case of the Acquiring Fund), called Creation Units. Creation Units are issued and redeemed typically for an in-kind basket of securities. Except when aggregated in Creation Units, shares of the Acquiring Fund are not redeemable securities of the Acquiring Fund.

Individual shares of the Acquiring Fund may only be purchased and sold on secondary markets through a financial intermediary, such as a broker-dealer or a bank. Because the Acquiring Fund's shares trade at market prices rather than NAV, shares may trade at a price greater than NAV (a premium) or less than NAV (a discount). You may incur costs attributable to the difference between the highest price a buyer is willing to pay to purchase shares of the ETF (bid) and the lowest price a seller is willing to accept for shares of the ETF (ask) when buying or selling shares in the secondary market (the bid/ask spread). Recent information, including information regarding the Acquiring Fund's NAV, market price, premiums and discounts, and bid/ask spread, is available at columbiathreadneedleus.com/etfs.

Shares of the Acquiring Fund do not have an investment minimum. Additional information and specific instructions explaining how to buy shares of the Acquiring Fund are outlined in the Acquiring Fund's Prospectus under the section "Buying and Selling Fund Shares."

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SYNOPSIS OF REORGANIZATION: COLUMBIA INTEGRATED LARGE CAP GROWTH FUND II INTO COLUMBIA LARGE CAP GROWTH ETF

Overview. Columbia Integrated Large Cap Growth Fund II and Columbia Large Cap Growth ETF:

Comparison of Investment Objectives, Principal Investment Strategies and Non-Fundamental Investment Policies. The investment objectives and principal investment strategies of the Target Fund and the Acquiring Fund are set forth in the table below. Each Fund's investment objective is non-fundamental and may be changed without shareholder approval. The Acquiring Fund and the Target Fund have substantially the same investment objective in that they each seek capital appreciation. The Funds have substantially the same investment strategies and policies (though the Acquiring Fund is an ETF and the Target Fund is permitted to invest in ETFs) and similar investment restrictions. In addition, the Target Fund may not sell securities short. Both Funds' investment policies with respect to 80% of their respective net assets may be changed by the Board without shareholder approval as long as shareholders are given 60 days' advance written notice of the change.

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Comparison of Fundamental Investment Policies. Both the Target Fund and Acquiring Fund have adopted certain fundamental investment policies. As described in the section of this Combined Information Statement/Prospectus entitled "Additional Information About the Reorganization - Board Considerations," one of the factors considered by the Board in approving the Reorganization was that the fundamental investment

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restrictions of the Target Fund and Acquiring Fund do not differ materially. The fundamental investment restrictions (i.e., those which may not be changed without shareholder approval) are listed below.

Fundamental investment policies cannot be changed without the approval of the holders of a majority of the outstanding shares of the applicable Fund. The term "majority of the outstanding shares" means the vote of (i) 67% or more of a Fund's shares present at a meeting, if more than 50% of the outstanding shares of the Fund are present or represented by proxy, or (ii) more than 50% of a Fund's outstanding shares, whichever is less.

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Comparison of Principal Risks. Acquiring Fund is subject to the principal risks described in "Section B - Additional Information Applicable to the Acquiring Fund" below. The Target Fund and Acquiring Fund are subject to many of the same principal risks, but such risks differ primarily due to the Acquiring Fund being an ETF.

Comparison of Management of the Funds. Columbia Threadneedle serves as investment manager for both the Target Fund and the Acquiring Fund, providing the Funds with investment research, advice, overall portfolio management and trade execution. In its capacity as investment manager, Columbia Threadneedle manages the day-to-day operations of the Funds. The Target Fund's management agreement with Columbia Threadneedle covers both investment advisory services and administrative services, and the management fee payable by the Target Fund under the agreement covers both advisory and administrative services. This fee is separate and apart from the other operating fees/expenses to which the Target Fund is subject. In contrast, the Acquiring Fund's management agreement with Columbia Threadneedle covers investment advisory services only and provides for a "unitary" fee which is intended to cover not only advisory and administrative services but also all other operating expenses of the Acquiring Fund except for the expenses specifically excluded from that arrangement, as described below under "Section B - Additional Information Applicable to the Acquiring Fund - The Investment Manager."

For the fiscal year ended March 31, 2026, the Target Fund paid Columbia Threadneedle a management fee of 0.66% of the Fund's average daily net assets before giving effect to the fee waiver described in more detail under "Summary - Fees and Expenses - Reorganization of Columbia Integrated Large Cap Growth Fund II into Columbia Large Cap Growth ETF." With respect to the Acquiring Fund, prior to March 16, 2026, the Predecessor Fund paid Columbia Threadneedle a management fee for investment advisory, administrative and accounting services, which was not a unitary fee like the Acquiring Fund's current fee structure. The Predecessor Fund's management services fee was paid annually at a rate equal to a percentage of the Predecessor Fund's daily net assets that declined from 0.75% to 0.55% as net assets increased. The effective management services fee rate for the Acquiring Fund's fiscal year ended March 31, 2026 was 0.75% and for the Predecessor Fund's fiscal year ended August 31, 2025 was 0.75% of average daily net assets. The Acquiring Fund's effective investment management fee rate for the period March 16, 2026 through March 31, 2026 was 0.35%. The table below shows the current contractual advisory fee schedule for each of the Funds. The Acquiring Fund's unitary management fee will apply following completion of the Reorganization.

The Acquiring Fund employs a unitary fee structure pursuant to which Columbia Threadneedle bears substantially all operating expenses of the Acquiring Fund, subject to certain exceptions. The unitary fee

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structure is described in more detail under "Summary - Fees and Expenses." Following the Reorganization, the total annual fund operating expenses of the Acquiring Fund are expected to be lower than those of the Target Fund. Class Inst is the oldest and only class of shares currently offered by the Target Fund.

Each Fund is governed by the Board (comprised of the same individuals), which is responsible for overseeing the Fund. For a listing of members of the Board, please refer to each Fund's Statement of Additional Information. The Funds have the same portfolio management teams. The Statement of Additional Information for each Fund provides additional information about portfolio manager compensation, other accounts managed and ownership of each Fund's shares. "Section B-Additional Information Applicable to the Acquiring Fund" below describes the employment history of the Acquiring Fund's portfolio managers.

Comparison of distribution payment policies and pricing arrangements.

Each Fund intends to pay out, in the form of distributions to shareholders, a sufficient amount of its income and gains so that the Fund will qualify for treatment as a regulated investment company under the Code (as defined below) and generally will not have to pay any U.S. federal income or excise tax. The distribution payment policies of the Funds are different with respect to the timing of distributions to shareholders. Each Fund generally intends to distribute any net realized capital gain (whether long-term or short-term gain) at least once a year. Normally, each Fund will declare and pay distributions of net investment income according to the following schedule:

Each Fund may declare or pay distributions of net investment income more frequently. Each Fund generally pays cash distributions within five business days after the distribution was declared. Each time a distribution is made, the NAV per share is reduced by the amount of the distribution.

The Funds have substantially the same procedures for calculating their share prices and valuing their portfolio securities. The Funds determine their NAV per share after the close of the NYSE (normally, 4:00 p.m., Eastern Time). The Funds will not be priced on days that the NYSE is closed for trading. For more information about the Funds' pricing procedures, you may refer to each Fund's prospectus, which accompanies this Combined Information Statement/Prospectus, under the section titled "Determination of Net Asset Value."

Comparison of Performance. Historical performance information for the Funds is set forth below.

Target Fund

The following bar chart and table show you how the Target Fund has performed in the past, and can help you understand the risks of investing in the Target Fund. The bar chart shows how the Target Fund's

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Institutional share performance (without sales charges) has varied for each full calendar year shown. The table below the bar chart compares the Target Fund's returns (after applicable sales charges shown in "Summary - Fees and Expenses - Reorganization of Columbia Integrated Large Cap Growth Fund II into Columbia Large Cap Growth ETF" above) for the periods shown with a broad measure of market performance, as well as another measure of performance for markets in which the Target Fund may invest.

The performance of one or more share classes shown in the table below begins before the indicated inception date for such share class. The returns shown include the returns of the Target Fund's Class A shares (adjusted to reflect the higher class-related operating expenses of each share class, where applicable) for periods prior to its inception date. Class A shares were offered prior to the inception date of Class Inst shares but have since been converted into the Target Fund's Class Inst shares.

Except for differences in annual returns resulting from differences in expenses and sales charges (where applicable), the share classes of the Target Fund would have substantially similar annual returns because all share classes of the Target Fund invest in the same portfolio of securities.

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs). The after-tax returns are shown only for Class Inst shares and will vary for other share classes. After-tax returns are shown for Class Inst shares are the oldest and only share class currently offered by the Target Fund.

The Target Fund's performance prior to July 2025 reflects returns achieved by one or more different subadvisers that managed the Fund according to different principal investment strategies. If the Target Fund's current subadvisers and strategies had been in place for the prior periods, results shown may have been different.

A Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free (800) 345-6611 or visiting columbiathreadneedleus.com.

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Target Fund - Columbia Integrated Large Cap Growth Fund II

CLASS INST SHARE PERFORMANCE

During the periods shown in the bar chart, the highest return for a calendar quarter was 27.17% (quarter ended June 30, 2020) and the lowest return for a calendar quarter was (21.12)% (quarter ended June 30, 2022).

The Target Fund's year-to-date total return as of June 30, 2026: 7.04%

Average Annual Total Returns After Applicable Sales Charges (for periods ended December 31, 2025)

* Returns shown for periods prior to the inception date for Class Inst shares include the returns of the Fund's Class A shares through January 2, 2017. Class A shares were offered prior to the inception date of the Fund's Class Inst shares but have since been merged into the Fund's Class Inst shares.

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Acquiring Fund

The following bar chart and table show you how the Acquiring Fund has performed in the past, and can help you understand the risks of investing in the Acquiring Fund. The bar chart shows how the Acquiring Fund's performance has varied for each full calendar year shown.

On March 16, 2026, the Acquiring Fund commenced operations and was reorganized and assumed the financial and performance history of the predecessor to the Acquiring Fund, Columbia Integrated Large Cap Growth Fund (the "Predecessor Fund"). Performance information shown for the Acquiring Fund's shares for all periods prior to March 16, 2026 is historical information for the Predecessor Fund's Class Institutional 3 (Class Inst3) shares.

The Predecessor Fund's performance prior to (i) November 18, 2025, reflects returns achieved by the Predecessor Fund pursuing the same investment objective and substantially similar principal investment strategies to those of the Acquiring Fund, (ii) December 5, 2025, reflects returns achieved by two different subadvisers that managed the Predecessor Fund prior to that date (one commencing in 2013 and the other commencing in 2022) pursuing the same investment objective and substantially similar principal investment strategies to those of the Acquiring Fund, (iii) January 21, 2022 reflects returns achieved by BMO Large-Cap Growth Fund (the "Former Predecessor Fund"), a series of BMO Funds, Inc, that was managed by BMO Asset Management Corp. and had the same investment objective and a substantially identical investment strategy to the Predecessor Fund as it operated prior to November 18, 2025.

Performance information has not been adjusted to reflect any differences in fees and expenses between the Predecessor Fund and the Acquiring Fund. If differences in fees and expenses were reflected, or had the Predecessor Fund been structured as an ETF, or had the Predecessor Fund pursued a different investment strategy, or had the Predecessor Fund not utilized one or both of its subadvisers, the returns for all periods shown may have differed.

The following bar chart and table show you how the Acquiring Fund (and the Former Predecessor Fund for periods prior to January 21, 2022 and the Predecessor Fund for the period from that date through March 16, 2026) has performed in the past, and can help you understand the risks of investing in the Fund. The bar chart shows how the Fund's performance has varied for each full calendar year shown. The table below the bar chart compares the Fund's returns for the periods shown with a broad measure of market performance, as well as another measure ofperformance for markets in which the Acquiring Fund may invest.

The after-tax returns shown in the Average Annual Total Returns table below are calculated using the highest historical individual U.S. federal marginal income tax rates in effect during the period indicated in the table and do not reflect the impact of state, local or foreign taxes. Your actual after-tax returns will depend on your personal tax situation and may differ from those shown in the table. In addition, the after-tax returns shown in the table do not apply to shares held in tax-advantaged accounts such as 401(k) plans or Individual Retirement Accounts (IRAs).

A Fund's past performance (before and after taxes) is no guarantee of how the Fund will perform in the future. Updated performance information can be obtained by calling toll-free (800) 426-3750 or visiting columbiathreadneedleus.com/etfs.

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During the periods shown in the bar chart, the highest return for a calendar quarter was 24.30% (quarter ended June 30, 2020) and the lowest return for a calendar quarter was (18.49)% (quarter ended June 30, 2022).

The Acquiring Fund's year-to-date total return as of June 30, 2026: 3.95%

Average Annual Total Returns (for periods ended December 31, 2025)

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ADDITIONAL INFORMATION ABOUT THE REORGANIZATION

Terms of The Reorganization. The Board has approved the Agreement. While shareholders are encouraged to review the Agreement, which has been filed with the SEC as an exhibit to the registration statement of which this Combined Information Statement/Prospectus is a part, the following is a summary of certain terms of the Agreement:

Conditions to Closing the Reorganization. In order for the Reorganization to be completed, all closing conditions must be satisfied or waived. The completion of the Reorganization is subject to certain conditions described in the Agreement, including among others:

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Termination of the Agreement. The Agreement and the transactions contemplated by it may be terminated with respect to the Reorganization by mutual agreement of CFST I and ETF Trust I at any time prior to the closing thereof, or by either CFST I or ETF Trust I in the event of a material breach of the Agreement by the other party or a failure of any condition precedent to the terminating party's obligations under the Agreement. In the event of a termination of the Reorganization, expenses associated with the Reorganization will be borne by Columbia Threadneedle.

U.S. Federal Income Tax Status of the Reorganization. The Reorganization is intended to qualify for U.S. federal income tax purposes as a tax-free reorganization under Section 368(a) of the Internal Revenue Code of 1986, as amended (the "Code"). As a condition to the closing of the Reorganization, the Target Fund and the Acquiring Fund will receive an opinion from Faegre Drinker Biddle & Reath LLP substantially to the effect that, on the basis of existing provisions of the Code, U.S. Treasury regulations issued thereunder, current administrative rules, pronouncements and court decisions, and certain representations, qualifications and customary assumptions with respect to the Reorganization, for U.S. federal income tax purposes:

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No private letter ruling will be sought from the Internal Revenue Service (the "IRS") with respect to the U.S. federal income tax consequences of the Reorganization. Opinions of counsel are not binding upon the IRS or the courts, are not guarantees of the tax results, and do not preclude the IRS from adopting or taking a contrary position, which may be sustained by a court. If the Reorganization were consummated but the IRS or the courts determine that the Reorganization did not qualify as a tax-free reorganization under the Code, the Target Fund would recognize gain or loss on the transfer of its assets to the Acquiring Fund and each shareholder of the Target Fund would recognize a taxable gain or loss for U.S. federal income tax purposes equal to the difference between its tax basis in its Target Fund shares and the fair market value of the Acquisition Shares it received in the Reorganization. Shareholders of the Target Fund should consult their tax advisers regarding the effect, if any, of the Reorganization in light of their individual circumstances, particularly if you hold shares in a taxable account.

A portion of the portfolio assets of the Target Fund is expected to be sold by the Target Fund prior to its Reorganization. The actual tax effect of any such sales depends on the difference between the price at which such portfolio assets are sold and the tax basis in such assets and the holding period of such assets. Any capital gains recognized in these sales on a net basis, after reduction by any available capital loss carryforwards, will be distributed to shareholders as capital gain dividends (to the extent of net long-term capital gains over net short-term capital losses) and/or ordinary dividends (to the extent of net short-term capital gains over net long-term capital losses) during or with respect to the year of sale, and such distributions will be taxable to shareholders. Prior to the closing of the Reorganization, the Target Fund will declare and pay a distribution to shareholders, which, together with all previous distributions, will have the effect of distributing to shareholders all of its investment company taxable income, net tax-exempt income, if any, and net realized capital gains, if any, through the closing of the Reorganization, and may include undistributed income or gains from prior years. These distributions will generally be taxable to shareholders that hold their shares in a taxable account. Such distributions may include distributions taxable as ordinary income or as long-term capital gains.

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A Fund's ability to carry forward capital losses and to use them to offset future gains may be limited as a result of the Reorganization. First, a Fund's "pre-acquisition losses" (including capital loss carryforwards, net current-year capital losses, and unrealized losses that exceed certain thresholds) may become unavailable to offset gains of the combined Fund to the extent such pre-acquisition losses exceed an annual limitation amount. Second, one Fund's pre-acquisition losses cannot be used to offset gains in another Fund that are unrealized ("built in") at the time of the Reorganization and that exceed certain thresholds ("non-de minimis built-in gains") for five tax years. Third, the Target Fund's capital loss carryforwards, as limited under the previous two rules, are permitted to offset only that portion of the capital gains of the Acquiring Fund for the taxable year of the Reorganization that is equal to the portion of the Acquiring Fund's taxable year that follows the date of the Reorganization (prorated according to number of days). Therefore, in certain circumstances, shareholders of a Fund may pay U.S. federal income tax sooner, or pay more U.S. federal income tax, than they would have had the Reorganization not occurred.

In addition, if the Reorganization qualifies as tax-free, the combined Fund will have tax attributes that reflect a blending of the tax attributes of each Fund at the time of the Reorganization (including as affected by the rules described above). Therefore, the shareholders of the Target Fund will receive a proportionate share of any unrealized gains in the combined Fund's assets, as well as any taxable income or gains realized by the Acquiring Fund but not distributed to its shareholders prior to the Reorganization, when such income or gains are eventually distributed by the Acquiring Fund. As a result, shareholders of the Target Fund may receive a greater amount of taxable distributions than they would have had the Reorganization not occurred. In addition, any pre-acquisition losses of the Target Fund (whether realized or unrealized) remaining after the operation of the limitation rules described above will become available to offset capital gains realized by the combined Fund after the Reorganization and thus may reduce subsequent capital gain distributions to a broader group of shareholders than would have been the case absent such Reorganization, such that the benefit of those losses to Target Fund shareholders may be further reduced relative to what the benefit would have been had the Reorganization not occurred.

The tax-free nature of the Reorganization and the realized and unrealized gains and losses of each Fund at the time of the Reorganization will determine the extent to which the combining Funds' respective losses will be available to reduce gains realized by the Acquiring Fund following the Reorganization, and consequently the extent to which the Acquiring Fund may be required to distribute gains to its shareholders earlier or in greater amounts than would have been the case absent the Reorganization. The effect of the rules described above will depend on the relative sizes of, and the losses and gains (both realized and unrealized) in, each Fund at the time of the Reorganization and thus cannot be calculated precisely prior to the Reorganization.

Capitalization. The following tables show the capitalization of the Target Fund and the Acquiring Fund as of the dates indicated and on a pro forma basis, assuming the proposed Reorganization had taken place as of the dates indicated.

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Reorganization of the Target Fund into the Acquiring Fund as of June 30, 2026

The information in the capitalization tables above is for informational purposes only. There is no assurance that the Reorganization will be consummated. Moreover, if consummated, the capitalization of the Target Fund and Acquiring Fund is likely to be different at the Closing Date as a result of daily share purchase and redemption activity in the Target Fund and the Acquiring Fund as well as due to market fluctuations. Accordingly, the foregoing should not be relied upon to reflect the number of shares of an Acquiring Fund that actually will be received on or after such date. For Information regarding the principal shareholders for the Target Fund, see "Exhibit B - Ownership of Fund Shares."

Board Considerations. The Reorganization was reviewed and unanimously approved with respect to the Target Fund at a meeting of the Board, with the advice and assistance of Fund counsel and independent legal counsel to the Board. The Board of the Acquiring Fund also unanimously approved the Reorganization. At a regular meeting of the Board and Committees thereof in June 2026, the Board considered the Reorganization of the Target Fund, as proposed by Columbia Threadneedle. In connection with those Board and Committee meetings, Columbia Threadneedle and its affiliates provided background materials, analyses and other information to the Board regarding, among other things, the topics discussed below, including responses to specific requests by the Board, and responded to questions raised by each Board and Committee member at those meetings.

After the Board reviewed, evaluated and discussed the materials, analyses and information provided to it that the Board considered relevant to its deliberations, a majority of the Board, including a majority of the trustees who are not "interested persons" (as defined in the 1940 Act) ("Independent Trustees") thereof voting separately, approved the Reorganization of the Target Fund. Prior to doing so, a majority of the Board, including a majority of the Independent Trustees, determined that participation by the Target Fund in its Reorganization was in the best interests of the Target Fund and that the interests of existing shareholders of the Target Fund would not be diluted as a result of the Reorganization.

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In considering the proposed Reorganization, the Board considered the following significant factors, among others and in no order of priority:

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The Board also considered that there may be circumstances where a Target Fund shareholder will not be able to hold shares of the Acquiring Fund. Shareholders of the Target Fund must have a brokerage account that is permitted to hold ETF shares in order to transact in shares of the Acquiring Fund. If Target Fund shareholders do not hold their Target Fund shares through a brokerage account that can hold shares of an ETF, their shares will be liquidated, and the proceeds will be sent to the shareholder of record and will be a taxable event. Additionally, omnibus retirement plan recordkeepers may not be able to include ETF shares on their platforms, and in such a

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case a retirement plan investor may be required by its retirement plan recordkeeper to redeem the Target Fund's shares prior to the Reorganization.

In addition, the Board considered that because the Acquiring Fund does not issue fractional shares, Target Fund shareholders will receive cash equivalent to (a) the value of fractional Acquisition Shares due to such shareholders and (b) to the net asset value of their Target Fund shares surrendered in the Reorganization as Cash-Out Shareholders, the distribution of which is expected to be de minimis and will be a taxable event to any such shareholder holding shares in a taxable account.

In their deliberations, the Board members did not identify any single factor that was paramount or controlling and individual Board members may have attributed different weights to various factors.

After consideration of these and other factors it deemed appropriate, the Board determined that the Reorganization of the Target Fund as proposed by Columbia Threadneedle is in the best interests of the Target Fund and its shareholders and that the interests of the existing shareholders of the Target Fund will not be diluted as a result of the Reorganization. The Board, including the Independent Trustees, unanimously approved the Reorganization of the Target Fund.

THE BOARD VOTED UNANIMOUSLY TO APPROVE THE REORGANIZATION AND THE AGREEMENT.

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SECTION B - ADDITIONAL INFORMATION APPLICABLE TO THE ACQUIRING FUND

Below is information regarding the Acquiring Fund. All references to a "Fund" in this Section B refer to the Acquiring Fund, unless otherwise noted.

Principal Risks of the Acquiring Fund

An investment in the Acquiring Fund involves risks. Descriptions of these risks are provided below the table. There is no assurance that the Acquiring Fund will achieve its investment objective and you may lose money. The value of the Acquiring Fund's holdings may decline, and the Acquiring Fund's NAV and share price may go down. Shares of the Fund bought on a trading exchange may fluctuate and you could lose money. An investment in the Acquiring Fund is not a bank deposit and is not insured or guaranteed by the Federal Deposit Insurance Corporation or any other government agency. The significance of any specific risk to an investment in the Acquiring Fund will vary over time depending on the composition of the Acquiring Fund's portfolio, market conditions, and other factors. You should read all of the risk information below carefully, because any one or more of these risks may result in losses to the Acquiring Fund.

Active Management Risk. Due to its active management, the Fund could underperform its benchmark index and/or other funds with similar investment objectives and/or strategies. Active trading of portfolio securities may result in added expenses, a lower return and increased tax liability, including relative to other ETFs.

Authorized Participant Concentration Risk. Only an Authorized Participant (as defined below) may engage in creation or redemption transactions directly with the Fund. The Fund has a limited number of institutions that may act as Authorized Participants, none of which are or will be obligated to engage in creation or redemption transactions. To the extent that these institutions exit the business or are unable or unwilling to proceed with creation and/or redemption orders with respect to the Fund and no other Authorized Participant is able or willing to step forward to create or redeem Creation Units, Fund shares may trade at a greater premium or discount between the market price and the NAV of the Fund's shares and/or wider bid/ask spreads than those experienced by other ETFs. Additionally, the Fund could possibly face trading halts and/or delisting from the Exchange. This risk is heightened in times of market stress, including at both the Fund share level and at the Fund holdings level.

Early/Late Close/Trading Halt Risk. An exchange or market may close early, close late or issue trading halts on specific securities, or the ability to buy or sell certain securities may be restricted, which may result in the Fund being unable to buy or sell these securities.

Equity Securities Risk. Equity securities may experience significant volatility. Such securities may fall sharply in response to adverse events affecting overall markets, a particular industry or sector, or an individual company's financial condition.

Fund Shares Liquidity Risk. Although the Fund's shares are listed on the Exchange, there can be no assurance that an active, liquid or otherwise orderly trading market for shares will be established or maintained by market makers or Authorized Participants, particularly in times of stressed market conditions. There is no guarantee that the Fund will be able to attract market makers and Authorized Participants. There is no obligation for market makers to make a market in the Fund's shares or for Authorized Participants to submit purchase or redemption orders for creation units. Accordingly, if such parties determine not to perform their respective functions, this could, such as during times of market stress, in turn, lead to variances between the market price of the Fund's shares and the underlying value of those shares and bid/ask spreads could widen. Trading in Fund shares on the Exchange also may be disrupted or even halted due to market conditions or for reasons that, in the view of the Exchange, make trading in Fund shares inadvisable. In addition, trading in Fund shares on the Exchange may be subject to trading halts caused by extraordinary market volatility pursuant to the Exchange

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"circuit breaker" rules. There also can be no assurance that the requirements of the Exchange necessary to maintain the listing of the Fund's shares will continue to be met or will remain unchanged.

Growth Securities Risk. Growth securities typically trade at a higher multiple of earnings than other types of equity securities. Accordingly, the market values of growth securities may never reach their expected market value and may decline in price. In addition, growth securities, at times, may not perform as well as value securities or the stock market in general, and may be out of favor with investors for varying periods of time. Growth securities may also be sensitive to movements in interest rates.

Issuer Risk. An issuer in which the Fund invests or to which it has exposure may perform poorly or below expectations, and the value of its securities may therefore decline, which may negatively affect the Fund's performance. Underperformance of an issuer may be caused by poor management decisions, competitive pressures, breakthroughs in technology, reliance on suppliers, labor problems or shortages, corporate restructurings, fraudulent disclosures, natural disasters, military confrontations and actions, war, other conflicts, terrorism, disease/virus outbreaks, epidemics or other events, conditions and factors which may impair the value of your investment in the Fund and could result in a greater premium or discount between the market price and the NAV of the Fund's shares and/or wider bid/ask spreads than those experienced by other ETFs.

Large-Cap Stock Risk. Investments in larger, more established companies (larger companies) may involve certain risks associated with their larger size. For instance, larger companies may be less able to respond quickly to new competitive challenges, such as changes in consumer tastes or innovation from smaller competitors. Also, larger companies are sometimes less able to achieve as high growth rates as successful smaller companies, especially during extended periods of economic expansion.

Market Price Relative to NAV Risk. Shares of the Fund may trade at prices that vary from Fund NAV. Shares of the Fund are listed for trading on the Exchange and are bought and sold in the secondary market at market prices that may differ, in some cases significantly, from their NAV. The NAV of the Fund will generally fluctuate with changes in the market value of the Fund's holdings. The market prices of shares, however, will generally fluctuate in response to changes in NAV, as well as the relative supply of, and demand for, Fund shares on the Exchange. Fund shares may trade at a greater premium or discount between the market price and the NAV of the Fund's shares and/or wider bid/ask spreads than those experienced by other ETFs. Columbia Threadneedle cannot predict whether Fund shares will trade below, at or above their NAV. Price differences may result because of, among other factors, supply and demand forces in the secondary trading market for Fund shares. It is expected that these forces generally will be closely related to, but not identical to, the same forces influencing the prices of the Fund's holdings. In this regard, if a shareholder purchases Fund shares at a time when the market price is at a premium to the NAV or sells shares at a time when the market price is at a discount to the NAV, the shareholder may sustain losses. Different investment strategies or techniques, including those intended to be defensive in nature, including, as examples, stop loss orders to sell an ETF's shares in the secondary market during negative market events or conditions, such as a "flash crash" or other market disruptions, may not work as intended and may produce significant losses to investors. Investors should consult their financial intermediary prior to using any such investment strategies or techniques, or before investing in the Fund.

Market Risk. The Fund may incur losses due to declines in the value of one or more securities in which it invests. These declines may be due to factors affecting a particular issuer, or the result of, among other things, political, regulatory, market, economic or social developments affecting the relevant market(s) more generally. In addition, turbulence in financial markets and reduced liquidity in equity, credit and/or fixed income markets may negatively affect many issuers, which could adversely affect the Fund's ability to price or value hard-to-value assets in thinly traded and closed markets and could cause significant redemptions and operational challenges. Global economies and financial markets are increasingly interconnected, and conditions and events in one country, region or financial market may adversely impact issuers in a different country, region or financial market. These risks may be magnified if certain events or developments adversely interrupt the global supply chain; in these and other circumstances, such risks might affect companies worldwide. As a result, local, regional

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or global events such as terrorism, war, other conflicts, natural disasters, disease/virus outbreaks and epidemics or other public health issues, recessions, depressions or other events - or the potential for such events - could have a significant negative impact on global economic and market conditions and could result in a greater premium or discount between the market price and the NAV of the Fund's shares and/or wider bid/ask spreads than those experienced by other ETFs.

Secondary Market Trading Risk. Investors buying or selling Fund shares will pay brokerage commissions or other charges imposed by brokers as determined by that broker. Brokerage commissions are often a fixed amount and may be a significant proportional cost for investors seeking to buy or sell relatively small amounts of Fund shares. In addition, secondary market investors will also incur the cost of the difference between the price that an investor is willing to pay for Fund shares (the bid price) and the price at which an investor is willing to sell Fund shares (the ask price). The Difference in bid and ask prices is often referred to as the "spread" or "bid/ask spread." The bid/ask spread varies over time for Fund shares based on trading volume and market liquidity, and is generally lower if the Fund's shares have more trading volume and market liquidity and higher if the Fund's shares have little trading volume and market liquidity. Further, increased market volatility may cause widening of bid/ask spreads.

Sector Risk. At times, the Fund may have a significant portion of its assets invested in securities of companies conducting business in a related group of industries within one or more economic sectors, including the information technology sector. Companies in the same sector may be similarly affected by economic, regulatory, political or market events or conditions, which may make the Fund vulnerable to unfavorable developments in that group of industries or economic sector.

Information Technology Sector. The Fund is vulnerable to the particular risks that may affect companies in the information technology sector. Companies in the information technology sector are subject to certain risks, including the risk that new services, equipment or technologies will not be accepted by consumers andbusinesses or will become rapidly obsolete. Performance of such companies may be affected by factors including obtaining and protecting patents (or the failure to do so) and significant competitive pressures, including aggressive pricing of their products or services, new market entrants, competition for market share and short product cycles due to an accelerated rate of technological developments. Such competitive pressures may lead to limited earnings and/or falling profit margins. As a result, the value of their securities may fall or fail to rise. In addition, many information technology sector companies have limited operating histories and prices of these companies' securities historically have been more volatile than other securities, especially over the short term. Some companies in the information technology sector are facing increased government and regulatory scrutiny and may be subject to adverse government or regulatory action, which could negatively impact the value of their securities.

Portfolio Managers. Information about the portfolio managers primarily responsible for overseeing the Acquiring Fund's investments is shown below. The Acquiring Fund's Statement of Additional Information ("SAI") provides additional information about the portfolio managers, including information relating to compensation, other accounts managed by the portfolio managers, and ownership by the portfolio managers of shares of the Acquiring Fund.

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Mr. Hans joined Columbia Threadneedle in December 2021. He previously served as a Director and PortfolioManager at BMO Asset Management Corp., which he joined in 2008. Mr. Hans began his investment career in 1998and earned a B.S. from Miami University and an M.B.A. from the University of Notre Dame.

Mr. Nusinzon joined Columbia Threadneedle in 2020. Mr. Nusinzon began his investment career in 1997 and earned a B.S.E. from the University of Pennsylvania and an M.B.A. from the Chicago Booth School of Business.

Dr. Sivaraman joined one of the Columbia Management legacy firms or acquired business lines in 2007. Dr.Sivaraman began his investment career in 2007 and earned a B.Tech. in Computer Science Engineering from theIndian Institute of Technology, Madras and a Ph.D. in Operations Research from the Massachusetts Institute ofTechnology.

Additional Investment Strategies and Policies. This section describes certain investment strategies and policies that the Fund may utilize in pursuit of its investment objective and some additional factors and risks involved with investing in the Fund.

In addition to any instruments mentioned in the Fund's principal investment strategies, the Fund may also invest in derivatives, including forward contracts (including forward foreign currency contracts), futures (including equity futures and index futures), options (including options on futures) and swaps (including portfolio and total return swaps), as well as cash, cash equivalents and money market instruments, such as repurchase agreements and money market funds (including affiliated money market funds).

Investment Guidelines

As a general matter, and except as specifically described in the discussion of the Fund's principal investment strategies in this Combined Information Statement/Prospectus or as otherwise required by the 1940 Act, the rules and regulations thereunder and any applicable exemptive relief, whenever an investment policy or limitation states a percentage of the Fund's assets that may be invested in any security or other asset or sets forth a policy regarding an investment standard, compliance with that percentage limitation or standard will be determined solely at the time of the Fund's investment in the security or asset.

Holding Other Kinds of Investments

The Fund may hold other investments that are not part of its principal investment strategies. These investments and their risks are described below and/or in the Fund's SAI. The Fund may choose not to invest in certain securities described herein and in the Fund's SAI, although it has the ability to do so. Information on the Fund's holdings can be found in the Fund's Form N-CSR or by visiting columbiathreadneedleus.com/etfs.

Transactions in Derivatives

The Fund may enter into derivative transactions. Derivatives are financial contracts whose values are, for example, based on (or "derived" from) traditional securities (such as a stock or bond), assets (such as a commodity like gold or a foreign currency), reference rates (such as the Secured Overnight Financing Rate (commonly known as "SOFR")) or market indices (such as the Standard & Poor's 500^® Index). The use of derivatives is a highly specialized activity which involves investment techniques and risks different from those associated with ordinary portfolio securities transactions. Derivatives involve special risks and may result in losses or may limit the Fund's potential gain from favorable market movements. Derivative strategies often involve leverage, which may exaggerate a loss, potentially causing the Fund to lose more money than it would

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have lost had it invested in the underlying security or other asset directly. The values of derivatives may move in unexpected ways, especially in unusual market conditions, and may result in increased volatility in the value of the derivative and/or the Fund's shares, among other consequences. The use of derivatives may also increase the amount of taxes payable by shareholders holding shares in a taxable account. Other risks arise from the Fund's potential inability to terminate or to sell derivative positions. A liquid secondary market may not always exist for the Fund's derivative positions at times when the Fund might wish to terminate or to sell such positions. Over-the-counter instruments (investments not traded on an exchange) may be illiquid, and transactions in derivatives traded in the over-the-counter market are subject to the risk that the other party will not meet its obligations. The use of derivatives also involves the risks of mispricing or improper valuation and that changes in the value of the derivative may not correlate perfectly with the underlying security, asset, reference rate or index. The Fund also may not be able to find a suitable derivative transaction counterparty, and thus may be unable to engage in derivative transactions when it is deemed favorable to do so, or at all. The U.S. government and the European Union (and some other jurisdictions) have enacted regulations and similar requirements that prescribe clearing, margin, reporting and registration requirements for participants in the derivatives market. These requirements are evolving and their ultimate impact on the Fund remains unclear, but such impact could include restricting and/or imposing significant costs or other burdens upon the Fund's participation in derivatives transactions. Additionally, regulations governing the use of derivatives by registered investment companies, such as the Fund, require, among other things, that a fund that invests in derivative instruments beyond a specified limited amount apply a value-at-risk-based limit to its portfolio and establish a comprehensive derivatives risk management program. As of the date of this prospectus, the Fund is not required to maintain a comprehensive derivatives risk management program given its more limited use of derivatives. For more information on the risks of derivative investments and strategies, see the Fund's SAI.

Affiliated Funds Investing in the Fund

Columbia Threadneedle or an affiliate serves as investment adviser to funds using Columbia brand ("Columbia Funds"), including those that are structured as "fund-of-funds", and provides asset-allocation services to (i) shareholders by investing in shares of other Columbia Funds, which may include the Fund (collectively referred to in this section as "Underlying Funds"), and (ii) discretionary managed accounts (collectively referred to as affiliated products) that invest exclusively in Underlying Funds. These affiliated products, individually or collectively, may own a significant percentage of the outstanding shares of one or more Underlying Funds, and Columbia Threadneedle seeks to balance potential conflicts of interest between the affiliated products and the Underlying Funds in which they invest. The affiliated products' investment in the Underlying Funds may have the effect of creating economies of scale, possibly resulting in lower expense ratios for the Underlying Funds, because the affiliated products may own substantial portions of the shares of Underlying Funds. However, redemption of Underlying Fund shares by one or more affiliated products could cause the expense ratio of an Underlying Fund to increase, as its fixed costs would be spread over a smaller asset base. Because of large positions of certain affiliated products, the Underlying Funds may experience relatively large inflows and outflows of cash due to affiliated products' purchases and sales of Underlying Fund shares. Although Columbia Threadneedle or its affiliate may seek to minimize the impact of these transactions where possible, for example, by structuring them over a reasonable period of time or through other measures, Underlying Funds may experience increased expenses as they buy and sell portfolio securities to manage the cash flow effect related to these transactions. Further, when Columbia Threadneedle or its affiliate structures transactions over a reasonable period of time in order to manage the potential impact of the buy and sell decisions for the affiliated products, those affiliated products, including funds-of-funds, may pay more or less (for purchase activity), or receive more or less (for redemption activity), for shares of the Underlying Funds than if the transactions were executed in one transaction. In addition, substantial redemptions by affiliated products within a short period of time could require the Underlying Fund to liquidate positions more rapidly than would otherwise be desirable, which may have the effect of reducing or eliminating potential gain or causing it to realize a loss. In order to meet such redemptions, an Underlying Fund may be forced to sell its liquid (or more liquid) positions, leaving the Underlying Fund holding, post-redemption, a relatively larger position in illiquid investments (i.e., any investment that the Fund reasonably expects cannot be sold or disposed of in current

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market conditions in seven calendar days or less without the sale or disposition significantly changing the market value of the investment) or less liquid securities. Substantial redemptions may also adversely affect the ability of the Underlying Fund to implement its investment strategy. Columbia Threadneedle or its affiliate also has a conflict of interest in determining the allocation of affiliated products' assets among the Underlying Funds, as it earns different fees from the various Underlying Funds.

Investing in Money Market Funds

The Fund may invest cash in, or hold as collateral for certain investments, shares of registered or unregistered money market funds, including funds advised by Columbia Threadneedle or its affiliates. These funds are not insured or guaranteed by the Federal Deposit Insurance Corporation (FDIC) or any other government agency. The Fund and its shareholders indirectly bear a portion of the expenses of any money market fund or other fund in which the Fund may invest.

Investing Defensively

The Fund may from time to time take temporary defensive investment positions that may be inconsistent with the Fund's principal investment strategies in attempting to respond to adverse market, economic, political, social or other conditions, including, without limitation, investing some or all of its assets in money market instruments or shares of affiliated or unaffiliated money market funds or holding some or all of its assets in cash or cash equivalents. The Fund may take such defensive investment positions for as long a period as deemed necessary. The Fund may not achieve its investment objective while it is investing defensively. Investing defensively may adversely affect Fund performance. During these times, the portfolio managers may make frequent portfolio holding changes, which could result in increased trading expenses and taxes, and decreased Fund performance.

Fund Website and Disclosure of Portfolio Holdings

Information about the Fund may be found at columbiathreadneedleus.com/etfs. Among other things, this website includes the Summary Prospectus, the prospectus and the SAI, when available, the Fund's annual and semiannual reports and information on the Fund's net asset value, market price, premiums/discounts, and bid-ask spreads, among other information.

Each day the Fund is open for business, it publicly disseminates the Fund's full portfolio holdings as of the close of the previous business day through its website at columbiathreadneedleus.com/etfs. In addition, the In-Kind Creation Basket and In-Kind Redemption Basket, which identify the securities and share quantities which may be delivered in exchange for purchases and redemptions of Creation Units as discussed below and in the SAI, are publicly disseminated each business day prior to the opening of trading on the Exchange via the National Securities Clearing Corporation ("NSCC").

Additional Information on Portfolio Turnover

A fund that replaces, or turns over, more than 100% of its investments in a year may be considered to have a high portfolio turnover rate. A high portfolio turnover rate can generate larger distributions of short-term capital gains to shareholders, which for individuals are generally taxable at higher rates than long-term capital gains for U.S. federal income tax purposes. Also, a high portfolio turnover rate can mean higher brokerage commissions and other transaction costs, which could reduce a fund's returns. In general, the greater the volume of buying and selling by a fund, the greater the impact that brokerage commissions and other transaction costs will have on its returns. The Fund may sell securities regardless of how long they've been held. A higher portfolio turnover rate may reduce the relative potential tax efficiency of the Fund compared with traditional mutual funds except potentially in cases where accomplished through redemptions in kind.

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Understanding Annual Fund Operating Expenses

The Fund's annual operating expenses, as presented in the Annual Fund Operating Expenses table in the "Section A - The Reorganization - Summary-Fees and Expenses" section of this Combined Information Statement/Prospectus, generally are based on estimated expenses for the Fund's current fiscal period and are expressed as a percentage (expense ratio) of the Fund's average net assets. The expense ratio reflects the Fund's fee arrangements as of the date of this Combined Information Statement/Prospectus. The Fund's annual operating expenses are comprised of (i) investment management fees and (ii) other expenses. No distribution or service fees are currently paid by the Fund, and there are no current plans to impose these fees.

Primary Service Provider Contracts

The Fund enters into contractual arrangements ("Service Provider Contracts") with various service providers, including, among others, Columbia Threadneedle, the administrator, the distributor, the transfer agent and the Fund's custodian. The Fund's Service Provider Contracts are solely among the parties thereto. Shareholders are not parties to, or intended to be third-party beneficiaries of, any Service Provider Contracts. Further, the Fund's prospectus, SAI and any Service Provider Contracts are not intended to give rise to any agreement, duty, special relationship or other obligation between the Fund and any investor, or give rise to any contractual, tort or other rights in any individual shareholder, group of shareholders or other person, including any right to assert a fiduciary or other duty, enforce the Service Provider Contracts against the parties or to seek any remedy thereunder, either directly or on behalf of the Fund. Nothing in the previous sentence should be read to suggest any waiver of any rights under federal or state securities laws.

The Investment Manager

Columbia Management Investment Advisers, LLC is located at 290 Congress Street, Boston, MA 02210 and serves as investment adviser to Columbia Funds, including the Fund. Columbia Threadneedle is a registered investment adviser and a wholly-owned subsidiary of Ameriprise Financial, Inc. ("Ameriprise Financial"). Columbia Threadneedle's management experience covers all major asset classes, including equity securities, debt instruments and money market instruments. In addition to serving as an investment adviser to traditional mutual funds, exchange-traded funds and closed-end funds, Columbia Threadneedle acts as an investment adviser for itself, its affiliates, individuals, corporations, retirement plans, private investment companies and financial intermediaries.

Subject to oversight by the Board, Columbia Threadneedle manages the day-to-day operations of the Fund.

The SEC has issued an order that permits Columbia Threadneedle, subject to the approval of the Board, to appoint affiliated and unaffiliated subadvisers by entering into subadvisory agreements with them, and to change in material respects the terms of those subadvisory agreements, including the fees paid thereunder, for the Fund without first obtaining shareholder approval, thereby avoiding the expense and delays typically associated with obtaining shareholder approval. The Fund furnishes shareholders with information about new subadvisers retained in reliance on the order within 90 days after hiring the subadviser. Columbia Threadneedle and its affiliates may have other relationships, including significant financial relationships, with current or potential subadvisers or their affiliates, which may create certain conflicts of interest. When making recommendations to the Board to appoint or to change a subadviser, or to change the terms of a subadvisory agreement, Columbia Threadneedle discloses to the Board the nature of any such material relationships. The SEC has issued a separate order that permits the Board to approve new subadvisory agreements or material changes to existing subadvisory agreements at a meeting that is not in person, provided that the Trustees are able to participate in the meeting using a means of communication that allows them to hear each other simultaneously during the meeting and other conditions of the order are satisfied. At present, Columbia Threadneedle has not engaged any investment subadviser for the Fund.

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The Fund pays Columbia Threadneedle a fee for its investment management services. The fee is calculated as a percentage of the daily net assets of the Fund and is paid monthly. The fee is 0.35% of the Fund's average daily net assets on all assets. In return for this fee (which is sometimes referred to as a unitary or unified fee), Columbia Threadneedle has agreed to pay the operating costs and expenses of the Fund other than the following expenses, which will be paid by the Fund: taxes, interest incurred on borrowing by the Fund, if any, brokerage fees and commissions, interest and fee expense related to the Fund's participation in inverse floater structures and any other portfolio transaction expenses, infrequent and/or unusual expenses, including without limitation litigation expenses, expenses incurred in connection with lending securities, and any other expenses approved by the Board.

A discussion regarding the basis for the Board's approval of the adoption of the Fund's investment management services agreement with Columbia Threadneedle is available in the Fund's Form N-CSR for the fiscal year period ended March 31, 2026.

Other Service Providers

ALPS Distributors, Inc., 1290 Broadway, Suite 1000, Denver, CO 80203, serves as the distributor of Creation Units for the Fund on an agency basis. The Distributor does not maintain a secondary market in shares.

State Street Bank and Trust Company, One Congress Street, Boston, MA 02114, serves as the administrator, fund accountant, transfer agent and custodian for the Fund.

PricewaterhouseCoopers LLP, 45 South Seventh Street, Suite 3400, Minneapolis, MN 55402, serves as the Fund's independent registered public accounting firm. The independent registered public accounting firm is responsible for auditing the annual financial statements of the Fund.

Other Roles and Relationships of Ameriprise Financial and its Affiliates - Certain Conflicts of Interest

Columbia Threadneedle provides various services to the Fund and other Columbia Funds for which it is compensated. Ameriprise Financial and its affiliates may also provide other services to these funds and be compensated for them.

Columbia Threadneedle and its affiliates may provide investment advisory and other services to other clients and customers substantially similar to those provided to the Fund. These activities, and other financial services activities of Ameriprise Financial and its affiliates, may present actual and potential conflicts of interest and introduce certain investment constraints.

Ameriprise Financial is a major financial services company, engaged in a broad range of financial activities beyond the fund-related activities of Columbia Threadneedle, including, among others, insurance, broker-dealer (sales and trading), asset management, banking and other financial activities. These additional activities may involve multiple advisory, financial, insurance and other interests in securities and other instruments, and in companies that issue securities and other instruments, that may be bought, sold or held by the Fund.

Conflicts of interest and limitations that could affect the Fund may arise from, for example, the following:

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Columbia Threadneedle and Ameriprise Financial have adopted various policies and procedures that are intended to identify, monitor and address conflicts of interest. However, there is no assurance that these policies, procedures and disclosures will be effective.

Additional information about Ameriprise Financial and the types of conflicts of interest and other matters referenced above is set forth in the Investment Management and Other Services - Other Roles and Relationships of Ameriprise Financial and its Affiliates - Certain Conflicts of Interest section of the Acquiring Fund's SAI. Investors should carefully review these disclosures and consult with their financial advisor if they have any questions.

Certain Legal Matters

Ameriprise Financial and certain of its affiliates are involved, in the normal course of business, in legal proceedings that include regulatory inquiries, arbitration and litigation (including class actions) concerning matters arising in connection with the conduct of their activities as part of a diversified financial services firm. Ameriprise Financial believes that the Fund is not currently the subject of, and that neither Ameriprise Financial nor any of its affiliates are the subject of, any pending legal, arbitration or regulatory proceedings that are likely to have a material adverse effect on the Fund or the ability of Ameriprise Financial or its affiliates to perform under their contracts with the Fund. Information regarding certain pending and settled legal proceedings may be found in the Fund's Form N-CSR and SAI. Additionally, Ameriprise Financial is required to make quarterly (10-Q), annual (10-K) and, as necessary, 8-K filings with the SEC on legal and regulatory matters that relate to Ameriprise Financial and its affiliates. Copies of these filings may be obtained by accessing the SEC website at sec.gov.

Buying and Selling Fund Shares

Shares of the Acquiring Fund are issued or redeemed by the Fund at NAV per share only in Creation Units, typically of 50,000 shares.

Shares trade on the secondary market, which is where most retail investors will buy and sell shares. It is expected that only a limited number of institutional investors will purchase and redeem shares directly from the Fund. Thus, certain information in the Fund's prospectus is not relevant to most retail investors. For example, information about buying and redeeming Creation Units directly from the Fund and about transaction fees imposed on such purchases and redemptions is not relevant to most retail investors.

Except when aggregated in Creation Units, the Acquiring Fund's shares are not redeemable with the Fund. Additional information about the procedures regarding creation and redemption of Creation Units (including the cut-off times for receipt of creation and redemption orders) is included in the Fund's SAI.

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Buying and Selling Acquiring Fund Shares on the Secondary Market

The Fund issues or redeems its shares at NAV per share only in Creation Units and only to Authorized Participants (or "APs"). Most investors will buy and sell shares in secondary market transactions through brokers or other financial intermediaries, and therefore must have an account with them to buy and sell shares. Shares can be bought or sold through your financial intermediary throughout the trading day like shares of any publicly traded issuer. When buying or selling shares through a financial intermediary, you will incur customary brokerage commissions and charges, and you may pay some or all of the spread between the bid and the offered prices in the secondary market for shares. The price at which you buy or sell shares (i.e., the market price) may be more (a premium to) or less than (a discount to) the NAV of the shares. Unless imposed by your financial intermediary, there is no minimum dollar amount you must invest in the Fund and no minimum number of shares you must buy. The Fund accommodates frequent purchases and redemptions of Creation Units by Authorized Participants and does not place a limit on purchases or redemptions of Creation Units by these investors. The Fund reserves the right, but does not have the obligation, to reject any purchase or redemption transaction at any time. With respect to foreign common stocks, the Fund may pay redemption proceeds more than seven (but no more than fifteen) calendar days after the Fund's shares are tendered for redemption as a result of local market holidays.

Shares of Columbia Large Cap Growth ETF are listed on NYSE Arca, Inc. ("NYSE Arca" or the "Exchange") under the symbol: REGS.

NYSE Arca is generally open Monday through Friday and is closed for weekends and the following holidays: New Year's Day, Martin Luther King, Jr. Day, Presidents' Day, Good Friday, Memorial Day, Juneteenth National Independence Day, Independence Day, Labor Day, Thanksgiving Day, and Christmas Day.

For information about buying and selling shares on the Exchange or in the secondary markets, please contact your financial intermediary.

Book Entry. Shares are held in book entry form, which means that no stock certificates are issued. The Depository Trust Company ("DTC"), or its nominee, is the registered owner of all outstanding shares of the Fund and is recognized as the owner of all shares. Participants in DTC include securities brokers and dealers, banks, trust companies, clearing corporations and other institutions that directly or indirectly maintain a custodial relationship with DTC. As a beneficial owner of shares, you are not entitled to receive physical delivery of Fund Shares certificates or to have shares registered in your name, and you are not considered a registered owner of shares. Therefore, to exercise any right as an owner of shares, you must rely on the procedures of DTC and its participants. These procedures are the same as those that apply to any stocks that you hold in book entry or "street name" through your brokerage account. Your account information will be maintained by your financial intermediary, which will provide you with account statements, confirmations of your purchases and sales of shares, and other information. Your financial intermediary also will be responsible for distributing income dividends and capital gain distributions and for ensuring that you receive shareholder reports and other communications from the Fund.

Share Trading Prices. The trading prices of the Fund's shares may differ from the Fund's daily NAV and can be affected by market forces of supply and demand for the Fund's shares, the prices of the Fund's investments, economic conditions and other factors. The Exchange or another market information provider intends to disseminate the approximate value of the Fund's portfolio every fifteen seconds. This approximate value should not be viewed as a "real-time" update of the NAV of the Fund because the approximate value may not be calculated in the same manner as the NAV, which is computed once a day. The quotations for certain investments may not be updated during U.S. trading hours if such holdings do not trade in the U.S., except such quotations may be updated to reflect currency fluctuations. The Fund is not involved in, or responsible for, the calculation or dissemination of the approximate values and makes no warranty as to the accuracy of these values.

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Additional Information about Buying and Selling Acquiring Fund Shares

Continuous Offering. Authorized Participants should be aware of certain legal risks unique to investors purchasing Creation Units directly from the Fund. Because shares may be issued on an ongoing basis, a "distribution" of shares could be occurring at any time. Certain activities that Authorized Participants perform with respect to the sale of shares could, depending on the circumstances, result in Authorized Participants being deemed to be a participant in the distribution, in a manner that could render Authorized Participants a statutory underwriter and subject Authorized Participants to the prospectus delivery and liability provisions of the Securities Act of 1933, as amended (the "Securities Act"). For example, Authorized Participants could be deemed a statutory underwriter if Authorized Participants purchase Creation Units from the issuing Fund, break them down into the constituent shares, and sell those shares directly to customers, or if Authorized Participants choose to couple the creation of a supply of new shares with an active selling effort involving solicitation of secondary market demand for shares. Whether a person is an underwriter for purposes of the Securities Act depends upon all of the facts and circumstances pertaining to that person's activities, and the examples mentioned here should not be considered a complete description of all the activities that could cause Authorized Participants to be deemed an underwriter.

Broker-dealer firms should also note that dealers who are not "underwriters" but are effecting transactions in shares, whether or not participating in the distribution of shares, are generally required to deliver a prospectus. This is because the prospectus delivery exemption in Section 4(3) of the Securities Act is not available in respect of such transactions as a result of Section 24(d) of the 1940 Act. As a result, broker-dealer firms should note that dealers who are not "underwriters" but are participating in a distribution (as opposed to engaging in ordinary secondary market transactions), and thus dealing with shares as part of an unsold allotment within the meaning of Section 4(3)(C) of the Securities Act, will be unable to take advantage of the prospectus delivery exemption provided by Section 4(3) of the Securities Act. For delivery of prospectuses to exchange members, the prospectus delivery mechanism of Rule 153 under the Securities Act is only available with respect to transactions on a national exchange.

Active Investors and Market Timing

With respect to the Acquiring Fund, the Board has determined not to adopt policies and procedures designed to prevent or monitor for frequent purchases and redemptions of the Fund's shares because investors primarily transact in Fund shares on the secondary market. Frequent trading of shares on the secondary market does not disrupt portfolio management, increase the Fund's trading costs, lead to realization of capital gains or otherwise harm Fund shareholders because these trades do not involve the issuance or redemption of Fund shares.

The Fund sells and redeems its shares at NAV only in Creation Units pursuant to the terms of a Participant Agreement between an Authorized Participant and the Distributor, and accepted by the Transfer Agent, principally in exchange for a basket of securities. With respect to such trades directly with the Fund to the extent effected in-kind (i.e., for securities), they generally would not cause the harmful effects that may result from frequent cash trades.

The Board recognizes that to the extent that the Fund allows or requires trades to be effected in whole or in part in cash, those trades could result in dilution to a Fund and increased transaction costs, which could negatively impact the Fund's ability to achieve its investment objective. The Board also recognizes, however, that direct trading by Authorized Participants is critical to ensuring that the Fund's shares trade at or close to NAV. Further, the Fund may employ fair valuation pricing to minimize the potential for dilution. Moreover, the Fund imposes transaction fees on purchases and redemptions of Creation Units reflecting the fact that the Fund's costs increase in those circumstances. The Fund reserves the right to impose additional restrictions on disruptive, excessive or short-term purchases.

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Determination of Net Asset Value

Equity securities listed on an exchange are typically valued at the closing price or last trade on their primary exchange at the close of business of the NYSE. Equity securities without a readily available closing price or that are not listed on any exchange are typically valued at the mean between the closing bid and asked prices. Other equity securities, debt securities and other assets are valued differently. For instance, bank loans trading in the secondary market are fair valued unless market quotations are readily available, fixed income investments maturing in 60 days or less are valued primarily using the amortized cost method, unless this methodology results in a valuation that does not approximate the market value of these securities, and those maturing in excess of 60 days are valued based on prices obtained from a pricing service, if available (which may represent market values or fair values). Investments in other open-end funds are valued at their published NAVs. The value of the Fund's portfolio securities is determined in accordance with the valuation policy approved by the Board (the Valuation Policy). Pursuant to Rule 2a-5 under the 1940 Act, the Board has designated Columbia Threadneedle as the Fund's valuation designee. Columbia Threadneedle, in turn, has authorized its valuation committee to make fair value determinations and to carry out supervisory and certain other functions relating to the valuation of Fund portfolio securities, pursuant to the Valuation Policy.

If a market price is not readily available or is deemed not to reflect market value for a portfolio security, the Investment Manager will determine the price based on a determination of the security's fair value pursuant to the Valuation Policy. In addition, Columbia Threadneedle may use fair valuation techniques to price securities that trade on a foreign exchange when a significant event has occurred after the foreign exchange closes but before the time at which the Fund's share price is calculated. Foreign exchanges typically close before the time at which Fund share prices are calculated, and may be closed altogether on some days when the Fund is open. Such significant events affecting a foreign security may include, but are not limited to: (1) corporate actions, earnings announcements, litigation or other events impacting a single issuer; (2) governmental action that affects securities in one sector or country; (3) natural disasters or armed conflicts affecting a country or region; or

38

(4) significant domestic or foreign market fluctuations. The Fund uses various criteria in determining whether a foreign security's market price is readily available and reflective of market value and, if not, the fair value of the security.

Fair valuation may have the effect of reducing stale pricing arbitrage opportunities presented by the pricing of Fund shares. However, when Columbia Threadneedle uses fair valuation to price equity securities, it may value those securities higher or lower than another fund or manager would. Also, fair valuation of Fund holdings may cause the Fund's performance to diverge to a greater degree from the performance of various benchmark indices used to compare the Fund's performance because indices generally do not use fair valuation techniques. Because of the judgment involved in fair valuation decisions, there can be no assurance that the value ascribed to a particular security is accurate.

Distributions and Taxes

Distributions to Shareholders. A fund can make money two ways:

Funds make payments of fund earnings to shareholders, distributing them among all shareholders of the fund. As a shareholder, you are entitled to your portion of a fund's distributed income, including capital gains. Reinvesting your distributions buys you more shares of a fund - which lets you take advantage of the potential for compound growth. Putting the money you earn back into your investment means it, in turn, may earn even more money (or be exposed to additional losses, if the fund earns a negative return). Over time, the power of compounding has the potential to significantly increase the value of your investment. There is no assurance, however, that you'll earn more money if you reinvest your distributions rather than receive them in cash.

Brokers may make available to their customers who own shares the DTC book-entry dividend reinvestment service. To determine whether the dividend reinvestment service is available and whether there is a commission or other charge for using this service, consult your broker. Brokers may require Fund shareholders to adhere to specific procedures and timetables. If this service is available and used, dividend distributions of both income and net realized gains will be automatically reinvested in additional whole shares of the distributing Fund purchased in the secondary market. Without this service, investors would receive their distributions in cash.

The Fund intends to pay out, in the form of distributions to shareholders, a sufficient amount of its income and gains so that the Fund will qualify for treatment as a regulated investment company and generally will not have to pay any federal income or excise tax. The Fund generally intends to distribute any net realized capital gain (whether long-term or short-term gain) at least once a year. Normally, the Fund will declare and pay distributions of net investment income according to the following schedule:

The Fund may declare or pay distributions of net investment income more frequently.

39

Each time a distribution is made, the NAV per share is reduced by the amount of the distribution.

The Fund generally pays cash distributions within five business days after the distribution was declared. If you sell all of your shares after the record date, but before the payment date, for a distribution, you'll normally receive that distribution in cash within five business days after the sale was made.

Unless you are a tax-exempt investor or holding Fund shares through a tax-advantaged account (such as a 401(k) plan or IRA), you should consider avoiding buying Fund shares shortly before the Fund makes a distribution (other than distributions of net investment income that are declared daily) of net investment income or net realized capital gain, because doing so can cost you money in taxes to the extent the distribution consists of taxable income or gains. This is because you will, in effect, receive part of your purchase price back in the distribution. This is known as "buying a dividend." To avoid "buying a dividend," before you invest in a Fund, check the Fund's distribution schedule, which is available at Columbia Funds' website, columbiathreadneedleus.com, and/or by calling 800.426.3750.

Taxes. You should be aware of the following considerations applicable to the Fund:

40

41

Premium/Discount Information. Information on the Fund's net asset value, market price, premiums and discounts, and bid-ask spreads can be found at columbiathreadneedleus.com/etfs.

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Exhibit A

Financial Highlights

The financial highlights tables below are designed to help you understand the Target Fund's and the Acquiring Fund's financial performance.

Financial Highlights - Target Fund

The following table is intended to help you understand the financial performance of Columbia Integrated Large Cap Growth Fund II (the "Target Fund") for the past five fiscal years. Certain information reflects financial results for a single Fund share. Per share net investment income (loss) amounts are calculated based on average shares outstanding during the period. The total return in the table represents the rate that an investor would have earned (or lost) on an investment in the Fund assuming all dividends and distributions had been reinvested. Total return does not reflect payment of sales charges, if any. Total return and portfolio turnover are not annualized for periods of less than one year. The ratios of expenses and net investment income are annualized for periods of less than one year. The portfolio turnover rate is calculated without regard to purchase and sales transactions of short-term instruments and certain derivatives, if any. If such transactions were included, the Fund's portfolio turnover rate may be higher. A zero balance may reflect an amount rounding to less than $0.01 or 0.01%.This information has been audited by PricewaterhouseCoopers LLP, the independent registered public accounting firm for the Fund, whose report, along with the Fund's financial statements, is included in the Fund's Form N-CSR, which is available upon request.

Notes to Financial Highlights

A-1

Financial Highlights - Acquiring Fund

The following table is intended to help you understand the financial performance of Columbia Large Cap Growth ETF (the "Acquiring Fund"). Certain information reflects financial results for a single Acquiring Fund share. Per share net investment income (loss) for the past five fiscal years or, if shorter, the Fund's period of operations. The financial highlights for all periods shown are those of the Predecessor Fund. Certain information reflects financial results for a single Predecessor Fund share. For periods ended 2022 and thereafter, per share net investment income (loss) amounts are calculated based on average shares outstanding during the period. The total return in the table represents the rate that an investor would have earned (or lost) on an investment in the Predecessor Fund assuming all dividends and distributions had been reinvested. Total return and portfolio turnover are not annualized for periods of less than one year. The ratios of expenses and net investment income are annualized for periods of less than one year. The portfolio turnover rate is calculated without regard to purchase and sales transactions of short-term instruments, certain derivatives and in-kind transactions, if any. If such transactions were included, the Predecessor Fund's portfolio turnover rate may be higher. A zero balance may reflect an amount rounding to less than $0.01 or 0.01%. The information for the three most recent fiscal years has been audited by PricewaterhouseCoopers LLP, the independent registered public accounting firm for the Fund and the Predecessor Fund, whose report, along with the Predecessor Fund's financial statements, is included in the Predecessor Fund's Form N-CSR, which is available upon request. The information for the fiscal year ended August 31, 2022 has been derived from the financial statements audited by the Predecessor Fund's former independent registered public accounting firm and, for the fiscal year ended August 31, 2021, audited by the Former Predecessor Fund's independent registered public accounting firm.

Notes to Financial Highlights

A-2

A-3

Exhibit B

Ownership of Fund Shares

Each person who owns, directly or indirectly, of record more than 25% of the outstanding shares of a Fund, by virtue of its fiduciary roles with respect to its clients or otherwise, may be deemed to be a "control person" (as that term is defined in the 1940 Act) of a Fund. A control person may be able to facilitate shareholder approval of proposals it favors and to impede shareholder approval of proposals it opposes. In this regard, if a control person owns a sufficient number of a Fund's outstanding shares, then, for certain shareholder proposals, such control person may be able to approve, or to prevent approval, of such proposals without regard to votes by other Fund shareholders.

As of June 30, 2026 the Acquiring Fund did not have any control persons. If the Reorganizations were to occur as of June 30, 2026, the Acquiring Fund would not have any control persons.

The following table provides information on each person who may be deemed to be a control person of a Fund as of June 30, 2026 because it owns, directly or indirectly, of record more than 25% of the outstanding shares of such Fund, by virtue of its fiduciary roles with respect to its clients or otherwise. The table also provides information on shareholders who owned of record or, to the knowledge of a Fund, beneficially, more than 5% of any class of the Fund's outstanding shares as of June 30, 2026. As of May 31, 2026, the officers and directors/trustees of each Fund, as a group, owned less than 1% of the outstanding shares of each class of such Fund.

B-1

Exhibit C

Comparison of Organizational Documents

The table below highlights certain key terms of the Declarations of Trust and By-Laws of the Target Fund and the Acquiring Fund.

C-1

C-2

C-3

C-4

C-5

C-6

C-7

The information contained in this Statement of Additional Information is not complete and may be changed. We may not sell these securities until the registration statement filed with the Securities and Exchange Commission is effective. This Statement of Additional Information is not an offer to sell these securities, and it is not soliciting an offer to buy these securities, in any jurisdiction where the offer or sale is not permitted.

SUBJECT TO COMPLETION, DATED JULY 17, 2026

STATEMENT OF ADDITIONAL INFORMATION

August 17, 2026

This Statement of Additional Information (the "SAI") relates to the reorganization (the "Reorganization") of Columbia Integrated Large Cap Growth Fund II (the "Target Fund"), a series of Columbia Funds Series Trust I ("CFST I") into Columbia Large Cap Growth ETF (the "Acquiring Fund"), a series of Columbia ETF Trust I ("ETF Trust I").

This SAI contains information which may be of interest to shareholders of the Target Fund, but which is not included in the combined Information Statement/Prospectus dated August 17, 2026 (the "Combined Information Statement/Prospectus") which relates to the Reorganization.

This SAI is not a prospectus and should be read in conjunction with the Combined Information Statement/Prospectus. As described in the Combined Information Statement/Prospectus, the Reorganization would involve: (i) the acquisition of the assets and assumption of the liabilities and obligations of the Target Fund by the Acquiring Fund in exchange for shares of the Acquiring Fund ("Acquisition Shares") of equal value to the net assets of the Target Fund being acquired (less the value of any cash delivered to the Target Fund for distribution to Target Fund shareholders (a) in lieu of any fractional Acquisition Shares that would have otherwise been distributable to such shareholders and (b) who do not have a brokerage account to receive Acquiring Fund Shares and instead receive a distribution of cash equal to the net asset value of their Target Fund shares surrendered in the Reorganization ("Cash-Out Shareholders")); (ii) the pro rata distribution of such shares to the shareholders of the Target Fund, with cash distributed (a) in lieu of fractional Acquisition Shares and (b) to Cash-Out Shareholders, and (iii) the complete liquidation and dissolution of the Target Fund, all upon the terms and conditions set forth in the Agreement and Plan of Reorganization (the "Agreement"). The Combined Information Statement/Prospectus has been filed with the Securities and Exchange Commission and is available upon request and without charge at columbiathreadneedleus.com, by calling toll-free 800.426.3750, or by writing to Columbia Funds, 290 Congress Street, Boston, Massachusetts 02210.

TABLE OF CONTENTS

ADDITIONAL INFORMATION ABOUT THE ACQUIRING FUND AND THE TARGET FUND

The following documents have been filed with the Securities and Exchange Commission (the "SEC") and are incorporated into this SAI by reference:

Acquiring Fund: Columbia Large Cap Growth ETF (SEC File nos. 333-209996 and 811-22736)

Target Fund: Columbia Integrated Large Cap Growth Fund II (SEC File nos. 2-99356 and 811-04367)

INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM

The Board of Trustees of the Acquiring Fund, including the trustees who are not "interested persons," as defined in the Investment Company Act of 1940, of ETF Trust I, has selected PricewaterhouseCoopers LLP ("PwC"), 45 South Seventh Street, Suite 3400 Minneapolis, Minnesota 55402, to act as the independent registered public accounting firm for the Acquiring Fund, providing audit and tax return review services and assistance and consultation in connection with the review of various SEC filings.

The audited financial statements of Columbia Integrated Large Cap Growth Fund II filed on Form N-CSR for the fiscal year ended March 31, 2026 are incorporated by reference into this SAI and have been so included and incorporated in reliance upon the reports of PwC, given their authority as experts in auditing and accounting.

The audited financial statements of Columbia Large Cap Growth ETF (and its predecessor fund) filed on Form N-CSR for the fiscal year ending March 31, 2026 are incorporated by reference into this SAI and have been so included and incorporated in reliance upon the reports of PwC, given their authority as experts in auditing and accounting.

SUPPLEMENTAL FINANCIAL INFORMATION

The following supplemental financial information regarding the Acquiring Fund is provided pursuant to Rule 6-11(d)(2) under Regulation S-X in lieu of pro forma financial statements for the Acquiring Fund that would otherwise be required under Regulation S-X.

1

2

COLUMBIA ETF TRUST I

PART C

OTHER INFORMATION

PART C. OTHER INFORMATION

Item 15. - Indemnification

Article Five of the Bylaws of Registrant provides that Registrant shall indemnify each of its trustees and officers (including persons who serve at Registrant's request as directors, officers or trustees of another organization in which Registrant has any interest as a shareholder, creditor or otherwise) who are not employees or officers of any investment adviser to Registrant or any affiliated person thereof and its chief compliance officer, regardless of whether such person is an employee or officer of any investment adviser to Registrant or any affiliated person thereof, and each of its other trustees and officers (including persons who serve at Registrant's request as directors, officers or trustees of another organization in which Registrant has any interest as a shareholder, creditor or otherwise) (i.e., those who are employees or officers of any investment adviser to Registrant or any affiliated person thereof) (Covered Persons) to the fullest extent authorized by applicable law against all liabilities and expenses in connection with the defense or disposition of any proceeding in which such Covered Person may be or may have been involved or with which such Covered Person may be or may have been threatened, while in office or thereafter, by reason of any alleged act or omission as a trustee or officer or by reason of his or her being or having been such a Covered Person, all as more fully set forth in the Registrant's Bylaws, which have been filed as an exhibit to this registration statement.

Section 17(h) of the Investment Company Act of 1940 (the 1940 Act) provides that no instrument pursuant to which Registrant is organized or administered shall contain any provision which protects or purports to protect any trustee or officer of Registrant against any liability to Registrant or its shareholders to which he or she would otherwise be subject by reason of willful misfeasance, bad faith, gross negligence, or reckless disregard of the duties involved in the conduct of his or her office.

The Registrant's Declaration of Trust provides that nothing in the Declaration of Trust shall protect any trustee or officer against any liabilities to the Registrant or its shareholders to which he or she would otherwise be subject by reason of willful misfeasance, bad faith, gross negligence or reckless disregard of the duties involved in the conduct of his or her office or position with or on behalf of the Registrant and the Registrant's Bylaws provides that no indemnification will be made in violation of the provisions of the 1940 Act.

The Registrant may be party to other contracts that include indemnification provisions for the benefit of the Registrant's trustees and officers.

The trustees and officers of the Registrant and the personnel of the Registrant's investment adviser are insured under an errors and omissions liability insurance policy. Registrant's investment adviser, Columbia Management Investment Advisers, LLC, maintains investment advisory professional liability insurance to insure it, for the benefit of Registrant and its non-interested trustees, against loss arising out of any effort, omission, or breach of any duty owed to Registrant or any series of Registrant by Columbia Management Investment Advisers, LLC.

Insofar as indemnification for liabilities arising under the Securities Act of 1933 (the 1933 Act) may be permitted to trustees, officers and controlling persons of the Registrant by the Registrant pursuant to the Registrant's organizational instruments or otherwise, the Registrant is aware that in the opinion of the Securities and Exchange Commission (SEC), such indemnification is against public policy as expressed in the 1933 Act and, therefore, is unenforceable.