Primary Offering Prospectus (Form 424B2)

Preliminary Pricing Supplement No. 9,366

Registration Statement Nos. 333-275587; 333-275587-01

Dated July 17, 2025

Filed pursuant to Rule 424(b)(2)

Morgan Stanley Finance LLC

Structured Investments

Callable Buffered Jump Securities due July 30, 2030

Based on the Performance of the SPDR® S&P® Biotech ETF

Fully and Unconditionally Guaranteed by Morgan Stanley

Principal at Risk Securities

￭The securities are unsecured obligations of Morgan Stanley Finance LLC ("MSFL") and are fully and unconditionally guaranteed by Morgan Stanley. The securities have the terms described in the accompanying product supplement, index supplement and prospectus, as supplemented or modified by this document. The securities do not provide for the regular payment of interest.

￭Call feature. We will redeem the securities on any redemption date, for a redemption payment that will increase over the term of the securities, if and only if the output of a risk neutral valuation model on a business day that is at least 2 but no more than 5 business days prior to such redemption date, based on the inputs indicated under "Call feature" below, indicates that redeeming on such date is economically rational for us as compared to not redeeming on such date. An early redemption of the securities will not automatically occur based on the performance of the underlier, and no further payments will be made on the securities once they have been redeemed.

￭Payment at maturity. If the securities have not been redeemed prior to maturity and the final level is greater than the initial level, investors will receive the stated principal amount plus the upside payment. If the final level is equal to or less than the initial level but is greater than or equal to the buffer level, investors will receive only the stated principal amount at maturity. If, however, the final level is less than the buffer level, investors will lose 1% for every 1% decline in the level of the underlier beyond the specified buffer amount. Under these circumstances, the payment at maturity will be less, and may be significantly less, than the stated principal amount of the securities, subject to the minimum payment at maturity.

￭The securities are for investors who are willing to risk their principal and forgo current income in exchange for the buffer feature and the possibility of receiving a redemption payment or payment at maturity that exceeds the stated principal amount. Investors in the securities must be willing to accept the risk of losing a significant portion of their initial investment. The securities are notes issued as part of MSFL's Series A Global Medium-Term Notes program.

￭All payments are subject to our credit risk. If we default on our obligations, you could lose some or all of your investment. These securities are not secured obligations and you will not have any security interest in, or otherwise have any access to, any underlying reference asset or assets.

(1)The securities will be sold only to investors purchasing the securities in fee-based advisory accounts.

(2)MS & Co. expects to sell all of the securities that it purchases from us to an unaffiliated dealer at a price of $ per security, for further sale to certain fee-based advisory accounts at the price to public of $1,000 per security. MS & Co. will not receive a sales commission with respect to the securities. See "Supplemental information regarding plan of distribution; conflicts of interest." For additional information, see "Plan of Distribution (Conflicts of Interest)" in the accompanying product supplement.

(3)See "Use of Proceeds and Hedging" in the accompanying product supplement.

The securities involve risks not associated with an investment in ordinary debt securities. See "Risk Factors" beginning on page 6.

The Securities and Exchange Commission and state securities regulators have not approved or disapproved these securities, or determined if this document or the accompanying product supplement, index supplement and prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The securities are not deposits or savings accounts and are not insured by the Federal Deposit Insurance Corporation or any other governmental agency or instrumentality, nor are they obligations of, or guaranteed by, a bank.

You should read this document together with the related product supplement, index supplement and prospectus, each of which can be accessed via the hyperlinks below. When you read the accompanying index supplement, please note that all references in such supplement to the prospectus dated November 16, 2023, or to any sections therein, should refer instead to the accompanying prospectus dated April 12, 2024 or to the corresponding sections of such prospectus, as applicable. Please also see "Additional Terms of the Securities" and "Additional Information About the Securities" at the end of this document.

References to "we," "us" and "our" refer to Morgan Stanley or MSFL, or Morgan Stanley and MSFL collectively, as the context requires.

Product Supplement for Principal at Risk Securities dated February 7, 2025 Index Supplement dated November 16, 2023

Prospectus dated April 12, 2024

Morgan Stanley Finance LLC

Redemption Dates and Redemption Payments

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Estimated Value of the Securities

The original issue price of each security is $1,000. This price includes costs associated with issuing, selling, structuring and hedging the securities, which are borne by you, and, consequently, the estimated value of the securities on the pricing date will be less than $1,000. Our estimate of the value of the securities as determined on the pricing date will be within the range specified on the cover hereof and will be set forth on the cover of the final pricing supplement.

What goes into the estimated value on the pricing date?

In valuing the securities on the pricing date, we take into account that the securities comprise both a debt component and a performance-based component linked to the underlier. The estimated value of the securities is determined using our own pricing and valuation models, market inputs and assumptions relating to the underlier, instruments based on the underlier, volatility and other factors including current and expected interest rates, as well as an interest rate related to our secondary market credit spread, which is the implied interest rate at which our conventional fixed rate debt trades in the secondary market.

What determines the economic terms of the securities?

In determining the economic terms of the securities, we use an internal funding rate, which is likely to be lower than our secondary market credit spreads and therefore advantageous to us. If the issuing, selling, structuring and hedging costs borne by you were lower or if the internal funding rate were higher, one or more of the economic terms of the securities would be more favorable to you.

What is the relationship between the estimated value on the pricing date and the secondary market price of the securities?

The price at which MS & Co. purchases the securities in the secondary market, absent changes in market conditions, including those related to the underlier, may vary from, and be lower than, the estimated value on the pricing date, because the secondary market price takes into account our secondary market credit spread as well as the bid-offer spread that MS & Co. would charge in a secondary market transaction of this type and other factors. However, because the costs associated with issuing, selling, structuring and hedging the securities are not fully deducted upon issuance, to the extent that MS & Co. may buy or sell the securities in the secondary market during the amortization period specified herein, absent changes in market conditions, including those related to the underlier, and to our secondary market credit spreads, it would do so based on values higher than the estimated value. We expect that those higher values will also be reflected in your brokerage account statements.

MS & Co. may, but is not obligated to, make a market in the securities, and, if it once chooses to make a market, may cease doing so at any time.

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Hypothetical Examples

The following hypothetical examples illustrate how to calculate the payment at maturity if we do not redeem the securities based on the output of a risk neutral valuation model prior to maturity. The following examples are for illustrative purposes only. The payment at maturity will be determined by reference to the closing level of the underlier on the observation date. The actual initial level and buffer level will be determined on the strike date. All payments on the securities are subject to our credit risk. The numbers in the hypothetical examples below may have been rounded for ease of analysis. The below examples are based on the following terms:

*The hypothetical initial level of $100.00 for the underlier has been chosen for illustrative purposes only and does not represent the actual initial level of the underlier. Please see "Historical Information" below for historical data regarding the actual closing levels of the underlier.

How to calculate the payment at maturity (if the securities have not been redeemed prior to maturity):

The hypothetical examples below illustrate how to calculate the payment at maturity if we do not redeem the securities based on the output of a risk neutral valuation model prior to maturity.

In example #1, the final level is greater than the initial level. Therefore, investors receive at maturity the stated principal amount plus 150% of the appreciation of the underlier over the term of the securities.

In example #2, the final level is equal to or less than the initial level but is greater than or equal to the buffer level. Therefore, investors receive at maturity the stated principal amount.

In example #3, the final level is less than the buffer level. Therefore, investors receive at maturity a payment that reflects a loss of 1% of principal for each 1% decline in the level of the underlier beyond the buffer amount.

If the securities have not been redeemed prior to maturity and the final level is less than the buffer level, you will be exposed to the negative performance of the underlier beyond the buffer amount at maturity, and your payment at maturity will be less, and may be significantly less, than the stated principal amount.

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Risk Factors

This section describes the material risks relating to the securities. For further discussion of these and other risks, you should read the section entitled "Risk Factors" in the accompanying product supplement and prospectus. We also urge you to consult with your investment, legal, tax, accounting and other advisers in connection with your investment in the securities.

Risks Relating to an Investment in the Securities

￭The securities provide for only the minimum payment at maturity and do not pay interest. The terms of the securities differ from those of ordinary debt securities in that they provide for only the minimum payment at maturity and do not pay interest. If we do not redeem the securities based on the output of a risk neutral valuation model prior to maturity and the final level is less than the buffer level, the payout at maturity will be an amount in cash that is less than the stated principal amount of each security, and you will lose an amount proportionate to the full decline in the level of the underlier over the term of the securities beyond the buffer amount. You could lose a significant portion of your initial investment in the securities.

￭If we redeem the securities based on the output of a risk neutral valuation model prior to maturity, the appreciation potential of the securities is limited by the fixed redemption payment specified for each redemption date. If we redeem the securities based on the output of a risk neutral valuation model on any redemption date, the appreciation potential of the securities is limited by the fixed redemption payment, and no further payments will be made on the securities once they have been redeemed. If the securities are redeemed prior to maturity, you will not participate in any appreciation of the underlier, which could be significant. The fixed redemption payment may be less than the payment at maturity you would receive had the securities not been redeemed and instead remained outstanding until maturity.

￭The securities are subject to early redemption risk. The term of your investment in the securities will be shortened if we redeem the securities based on the output of a risk neutral valuation model on any redemption date. In accordance with the risk neutral valuation model determination noted herein, it is more likely that we will redeem the securities when it would be advantageous for you to continue to hold them. As such, we will be more likely to redeem the securities when not redeeming the securities would result in an amount payable on the securities that is greater than instruments of a comparable maturity and credit rating trading in the market. If we redeem the securities prior to maturity, you will receive no further payments on the securities, may be forced to invest in a lower interest rate environment and may not be able to reinvest at comparable terms or returns.

On the other hand, we will be less likely to redeem the securities when the final level of the underlier is expected to be less than the initial level, such that you will not receive a positive return on the securities. Under no circumstances will we redeem the securities prior to the first redemption date.

￭The market price of the securities may be influenced by many unpredictable factors. Several factors, many of which are beyond our control, will influence the value of the securities in the secondary market and the price at which MS & Co. may be willing to purchase or sell the securities in the secondary market. We expect that generally the value of the underlier at any time will affect the value of the securities more than any other single factor. Other factors that may influence the value of the securities include:

othe volatility (frequency and magnitude of changes in value) of the underlier;

ointerest and yield rates in the market;

odividend rates on the underlier;

ogeopolitical conditions and economic, financial, political, regulatory or judicial events that affect the underlier or equity markets generally;

othe availability of comparable instruments;

othe occurrence of certain events affecting the underlier that may or may not require an adjustment to the adjustment factor;

othe composition of the underlier and changes in the component securities of the underlier;

othe time remaining until the securities mature; and

oany actual or anticipated changes in our credit ratings or credit spreads.

Some or all of these factors will influence the price that you will receive if you sell your securities prior to maturity. Generally, the longer the time remaining to maturity, the more the market price of the securities will be affected by the other factors described above. For example, you may have to sell your securities at a substantial discount from the stated principal amount if, at the time of sale, the closing level of the underlier is at, below or not sufficiently above the buffer level, or if market interest rates rise.

You can review the historical closing levels of the underlier in the section of this document called "Historical Information." You cannot predict the future performance of the underlier based on its historical performance. The value of the underlier may be, and has recently been, volatile, and we can give you no assurance that the volatility will lessen. There can be no assurance that the

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final level will be greater than or equal to the buffer level so that you do not suffer a loss on your initial investment in the securities.

￭The securities are subject to our credit risk, and any actual or anticipated changes to our credit ratings or credit spreads may adversely affect the market value of the securities. You are dependent on our ability to pay all amounts due on the securities, and, therefore, you are subject to our credit risk. The securities are not guaranteed by any other entity. If we default on our obligations under the securities, your investment would be at risk and you could lose some or all of your investment. As a result, the market value of the securities prior to maturity will be affected by changes in the market's view of our creditworthiness. Any actual or anticipated decline in our credit ratings or increase in the credit spreads charged by the market for taking our credit risk is likely to adversely affect the market value of the securities.

￭As a finance subsidiary, MSFL has no independent operations and will have no independent assets. As a finance subsidiary, MSFL has no independent operations beyond the issuance and administration of its securities and will have no independent assets available for distributions to holders of MSFL securities if they make claims in respect of such securities in a bankruptcy, resolution or similar proceeding. Accordingly, any recoveries by such holders will be limited to those available under the related guarantee by Morgan Stanley and that guarantee will rank pari passu with all other unsecured, unsubordinated obligations of Morgan Stanley. Holders will have recourse only to a single claim against Morgan Stanley and its assets under the guarantee. Holders of securities issued by MSFL should accordingly assume that in any such proceedings they would not have any priority over and should be treated pari passu with the claims of other unsecured, unsubordinated creditors of Morgan Stanley, including holders of Morgan Stanley-issued securities.

￭The rate we are willing to pay for securities of this type, maturity and issuance size is likely to be lower than the rate implied by our secondary market credit spreads and advantageous to us. Both the lower rate and the inclusion of costs associated with issuing, selling, structuring and hedging the securities in the original issue price reduce the economic terms of the securities, cause the estimated value of the securities to be less than the original issue price and will adversely affect secondary market prices. Assuming no change in market conditions or any other relevant factors, the prices, if any, at which dealers, including MS & Co., may be willing to purchase the securities in secondary market transactions will likely be significantly lower than the original issue price, because secondary market prices will exclude the issuing, selling, structuring and hedging-related costs that are included in the original issue price and borne by you and because the secondary market prices will reflect our secondary market credit spreads and the bid-offer spread that any dealer would charge in a secondary market transaction of this type as well as other factors.

The inclusion of the costs of issuing, selling, structuring and hedging the securities in the original issue price and the lower rate we are willing to pay as issuer make the economic terms of the securities less favorable to you than they otherwise would be.

However, because the costs associated with issuing, selling, structuring and hedging the securities are not fully deducted upon issuance, to the extent that MS & Co. may buy or sell the securities in the secondary market during the amortization period specified herein, absent changes in market conditions, including those related to the underlier, and to our secondary market credit spreads, it would do so based on values higher than the estimated value, and we expect that those higher values will also be reflected in your brokerage account statements.

￭The estimated value of the securities is determined by reference to our pricing and valuation models, which may differ from those of other dealers and is not a maximum or minimum secondary market price. These pricing and valuation models are proprietary and rely in part on subjective views of certain market inputs and certain assumptions about future events, which may prove to be incorrect. As a result, because there is no market-standard way to value these types of securities, our models may yield a higher estimated value of the securities than those generated by others, including other dealers in the market, if they attempted to value the securities. In addition, the estimated value on the pricing date does not represent a minimum or maximum price at which dealers, including MS & Co., would be willing to purchase your securities in the secondary market (if any exists) at any time. The value of your securities at any time after the date of this document will vary based on many factors that cannot be predicted with accuracy, including our creditworthiness and changes in market conditions. See also "The market price of the securities may be influenced by many unpredictable factors" above.

￭The securities will not be listed on any securities exchange and secondary trading may be limited. The securities will not be listed on any securities exchange. Therefore, there may be little or no secondary market for the securities. MS & Co. may, but is not obligated to, make a market in the securities and, if it once chooses to make a market, may cease doing so at any time. When it does make a market, it will generally do so for transactions of routine secondary market size at prices based on its estimate of the current value of the securities, taking into account its bid/offer spread, our credit spreads, market volatility, the notional size of the proposed sale, the cost of unwinding any related hedging positions, the time remaining to maturity and the likelihood that it will be able to resell the securities. Even if there is a secondary market, it may not provide enough liquidity to allow you to trade or sell the securities easily. Since other broker-dealers may not participate significantly in the secondary market for the securities, the price at which you may be able to trade your securities is likely to depend on the price, if any, at which MS & Co. is willing to transact. If, at any time, MS & Co. were to cease making a market in the securities, it is likely that there would be no secondary market for the securities. Accordingly, you should be willing to hold your securities to maturity.

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￭As discussed in more detail in the accompanying product supplement, investing in the securities is not equivalent to investing in the underlier(s).

￭The U.S. federal income tax consequences of an investment in the securities are uncertain. There is no direct legal authority regarding the proper U.S. federal income tax treatment of the securities, and significant aspects of the tax treatment of the securities are uncertain. Moreover, the securities may be subject to the "constructive ownership" regime, in which case certain adverse tax consequences may apply upon your disposition of a security. You should review carefully the section entitled "United States Federal Income Tax Considerations" herein, in combination with the section entitled "United States Federal Income Tax Considerations" in the accompanying product supplement, and consult your tax adviser regarding the U.S. federal income tax consequences of an investment in the securities.

Risks Relating to the Underlier(s)

￭Because your return on the securities will depend upon the performance of the underlier(s), the securities are subject to the following risk(s), as discussed in more detail in the accompanying product supplement.

oAdjustments to an underlying fund or the index tracked by such underlying fund could adversely affect the value of the securities.

oThe performance and market price of an underlying fund, particularly during periods of market volatility, may not correlate with the performance of its share underlying index, the performance of the component securities of its share underlying index or the net asset value per share of such underlying fund.

oThe anti-dilution adjustments the calculation agent is required to make do not cover every event that could affect an underlying fund.

￭The securities are subject to risks associated with investments in securities with a concentration in the biotechnology sector. The securities included in the S&P® Biotechnology Select Industry Index and that are generally tracked by the SPDR® S&P® Biotech ETF are securities of companies primarily engaged in research, development, manufacturing and/or marketing of products based on genetic analysis and genetic engineering. Industry-specific risks to which companies in the biotechnology sector are subject may include the following:

oafter spending heavily on research and development, their products or services may not prove commercially successful or may become obsolete quickly;

othe biotechnology industry may be subject to greater governmental regulation than other industries, and changes in governmental policies and the need for regulatory approvals may have a material adverse effect on the industry;

ocompanies in the biotechnology industry are subject to risks arising from new technologies and competitive pressures; and

ocompanies in the biotechnology industry are heavily dependent on patents and intellectual property rights. The loss or impairment of these rights may adversely affect the profitability of these companies.

The SPDR® S&P® Biotech ETF may be subject to increased price volatility as it is linked to a single industry, market or sector and may be more susceptible to adverse economic, market, political or regulatory occurrences affecting that industry, market or sector.

Risks Relating to Conflicts of Interest

In engaging in certain activities described below and as discussed in more detail in the accompanying product supplement, our affiliates may take actions that may adversely affect the value of and your return on the securities, and in so doing they will have no obligation to consider your interests as an investor in the securities.

￭The calculation agent, which is a subsidiary of Morgan Stanley and an affiliate of MSFL, will make determinations with respect to the securities. As calculation agent, MS & Co. will make any determinations necessary to calculate any payment(s) on the securities. Moreover, certain determinations made by MS & Co., in its capacity as calculation agent, may require it to exercise discretion and make subjective judgments, which may adversely affect your return on the securities. In addition, MS & Co. has determined the estimated value of the securities on the pricing date.

￭Hedging and trading activity by our affiliates could potentially adversely affect the value of the securities.

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Historical Information

SPDR® S&P® Biotech ETF Overview

Bloomberg Ticker Symbol: XBI UP

The SPDR® S&P® Biotech ETF is an exchange-traded fund that seeks investment results that correspond generally to the price and yield performance, before fees and expenses, of its share underlying index, which is the S&P® Biotechnology Select Industry Index. The underlying fund manager with respect to the SPDR® S&P® Biotech ETF is SPDR® Series Trust, which is a registered investment company. It is possible that the underlier may not fully replicate the performance of its share underlying index due to the temporary unavailability of certain securities in the secondary market or due to other extraordinary circumstances. Information provided to or filed with the Securities and Exchange Commission by the underlying fund manager pursuant to the Securities Act of 1933 and the Investment Company Act of 1940 can be located by reference to Securities and Exchange Commission file numbers 333-57793 and 811-08839, respectively, through the Securities and Exchange Commission's website at www.sec.gov. In addition, information regarding the underlier may be obtained from other sources including, but not limited to, press releases, newspaper articles and other publicly disseminated documents. Neither we nor the agent makes any representation that such publicly available documents or any other publicly available information regarding the underlier is accurate or complete.

The closing level of the underlier on July 16, 2025 was $87.82. The following graph sets forth the daily closing levels of the underlier for the period noted below. We obtained the historical information presented in this document from Bloomberg Financial Markets, without independent verification. The underlier has at times experienced periods of high volatility. You should not take the historical closing levels of the underlier as an indication of its future performance, and no assurance can be given as to the closing level of the underlier at any time.

This document relates only to the securities referenced hereby and does not relate to the underlier. We have derived all disclosures contained in this document regarding the underlier from the publicly available documents described above. In connection with this offering of securities, neither we nor the agent has participated in the preparation of such documents or made any due diligence inquiry with respect to the underlier. Neither we nor the agent makes any representation that such publicly available documents or any other publicly available information regarding the underlier is accurate or complete. Furthermore, we cannot give any assurance that all events occurring prior to the date hereof (including events that would affect the accuracy or completeness of the publicly available documents described above) that would affect the trading price of the underlier (and therefore the closing level of the underlier on the strike date) have been publicly disclosed. Subsequent disclosure of any such events or the disclosure of or failure to disclose material future events concerning the underlier could affect the value received with respect to the securities and therefore the value of the securities.

Neither we nor any of our affiliates makes any representation to you as to the performance of the underlier.

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We and/or our affiliates may presently or from time to time engage in business with the underlying fund manager. In the course of such business, we and/or our affiliates may acquire non-public information with respect to the underlier, and neither we nor any of our affiliates undertakes to disclose any such information to you. In addition, one or more of our affiliates may publish research reports with respect to the underlier. The statements in the preceding two sentences are not intended to affect the rights of investors in the securities under the securities laws. You should undertake an independent investigation of the underlier as in your judgment is appropriate to make an informed decision with respect to an investment linked to the underlier.

The securities are not sponsored, endorsed, sold, or promoted by the underlying fund manager. The underlying fund manager makes no representations or warranties to the owners of the securities or any member of the public regarding the advisability of investing in the securities. The underlying fund manager has no obligation or liability in connection with the operation, marketing, trading or sale of the securities.

S&P® Biotechnology Select Industry Index. The S&P® Biotechnology Select Industry Index (Bloomberg ticker: SPSIBI) is a modified equal weighted index designed to measure the performance of stocks in the S&P® Total Market Index that are classified as part of the Biotechnology sub-industry under the Global Industry Classification Standard. The share underlying index publisher with respect to the S&P® Biotechnology Select Industry Index is S&P® Dow Jones Indices LLC, or any successor thereof.

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Additional Terms of the Securities

Please read this information in conjunction with the terms on the cover of this document.

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Additional Information About the Securities

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