Primary Offering Prospectus (Form 424B2)

The information in this pricing supplement is not complete and may be changed. We may not deliver these securities until a final pricing supplement is delivered. This pricing supplement and the accompanying prospectus supplement and prospectus do not constitute an offer to sell these securities and we are not soliciting an offer to buy these securities in any jurisdiction where the offer or sale is not permitted.

Subject to Completion, Preliminary Pricing Supplement dated June 8, 2026

GLOBAL MEDIUM-TERM NOTES, SERIES J

Euro Fixed/Floating Rate Senior Registered Notes Due 2030

We, Morgan Stanley, may redeem the Global Medium-Term Notes, Series J, Euro Fixed/Floating Rate Senior Registered Notes Due 2030 (the "notes") (i) in whole or in part at any time on or after December , 2026 and prior to June , 2029 in accordance with the provisions described in the accompanying prospectus under the heading "Description of Debt Securities-Redemption and Repurchase of Debt Securities-Optional Make-whole Redemption of Debt Securities," as supplemented by the provisions below, (ii) (a) in whole but not in part, on June , 2029, or (b) in whole at any time or in part from time to time, on or after May , 2030, in each case at a redemption price equal to 100% of the principal amount to be redeemed plus accrued and unpaid interest thereon to but excluding the redemption date, in accordance with the provisions described in the accompanying prospectus under the heading "Description of Debt Securities-Redemption and Repurchase of Debt Securities-Notice of Redemption," as supplemented by the provisions below under the heading "Optional Redemption" and (iii) under the circumstances described under "Description of Notes-Tax Redemption" in the accompanying prospectus supplement.

Application will be made to the Financial Conduct Authority (the "FCA") (in its capacity as competent authority for the purposes of Part VI of the Financial Services and Markets Act 2000, as amended (the "FSMA")) for the notes described herein to be admitted to the Official List of the FCA and application will also be made to the London Stock Exchange plc for such notes to be admitted to trading on the Main Market of the London Stock Exchange plc after the original issue date. No assurance can be given that such applications will be granted.

We describe the basic features of the notes in the section of the accompanying prospectus supplement called "Description of Notes," subject to and as modified by the provisions described below. In addition, we describe the basic features of the notes during the Fixed Rate Period (as defined below) in the section of the accompanying prospectus called "Description of Debt Securities-Fixed Rate Debt Securities" and during the Floating Rate Period (as defined below) in the section of the accompanying prospectus called "Description of Debt Securities-Floating Rate Debt Securities," in each case subject to and as modified by the provisions described below.

Investing in the notes involves risks. See "Risk Factors" on page PS-5.

We describe how interest is calculated, accrued and paid during the Fixed Rate Period, including where a scheduled interest payment date is not a business day (the following unadjusted business day convention), under "Description of Debt Securities-Fixed Rate Debt Securities" in the accompanying prospectus. We describe how interest is calculated, accrued and paid during the Floating Rate Period, including the adjustment of scheduled interest payment dates for business days (except at maturity), under "Description of Debt Securities-Floating Rate Debt Securities" in the accompanying prospectus.

Terms not defined herein have the meanings given to such terms in the accompanying prospectus supplement and prospectus, as applicable.

Concurrently with this offering, we are offering £ aggregate principal amount of Global Medium-Term Notes, Series J, Pounds Sterling Fixed/Floating Rate Senior Registered Notes Due 2032 (the "new Sterling notes") in a separate registered public offering (the "concurrent offering"). We may sell more or fewer new Sterling notes in the concurrent offering depending on market and other conditions. The closing of this offering is not conditioned on the closing of the concurrent offering, and the closing of the concurrent offering is not conditioned on the closing of this offering. There can be no assurance that the concurrent offering will be consummated on the terms described above or at all. The foregoing description and other information regarding the concurrent offering is included herein solely for informational purposes. Nothing in this pricing supplement should be construed as an offer to sell, or a solicitation of an offer to buy, any new Sterling notes, and no part of the concurrent offering is incorporated by reference in this pricing supplement.

The notes 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.

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

MORGAN STANLEY

Neither Morgan Stanley nor any of the managers has authorized anyone to provide you with information other than that contained or incorporated by reference in this pricing supplement, the accompanying prospectus supplement, the accompanying prospectus and any free writing prospectus relating to this offering prepared by Morgan Stanley or on its behalf. Morgan Stanley and the managers take no responsibility for, and can provide no assurance as to the reliability of, any other information that others may give you. You should assume that the information appearing in this pricing supplement, the accompanying prospectus supplement, the accompanying prospectus and any related free writing prospectus and the documents incorporated herein or therein is accurate only as of their respective dates. Morgan Stanley is offering to sell the notes and is seeking offers to buy the notes, only in jurisdictions where such offers and sales are permitted.

NOTICE TO PROSPECTIVE INVESTORS IN THE EUROPEAN ECONOMIC AREA

None of this pricing supplement, the accompanying prospectus supplement, the accompanying prospectus or any related free writing prospectus is a "prospectus" for the purposes of Regulation (EU) 2017/1129, as amended.

Prohibition of sales to EEA retail investors - The notes are not intended to be offered, sold or otherwise made available to and should not be offered, sold or otherwise made available to any retail investor in the European Economic Area (the "EEA"). For these purposes, a "retail investor" means a person who is one (or both) of: (i) a retail client as defined in point (11) of Article 4(1) of Directive 2014/65/EU, as amended ("MiFID II"); or (ii) a customer within the meaning of Directive (EU) 2016/97, as amended, where that customer would not qualify as a professional client as defined in point (10) of Article 4(1) of MiFID II. Consequently, no key information document required by Regulation (EU) No 1286/2014, as amended (the "PRIIPs Regulation") for offering or selling the notes or otherwise making them available to retail investors in the EEA has been prepared and therefore offering or selling the notes or otherwise making them available to any retail investor in the EEA may be unlawful under the PRIIPs Regulation.

NOTICE TO PROSPECTIVE INVESTORS IN THE UNITED KINGDOM

Prohibition of sales to United Kingdom retail investors - The notes are not intended to be offered, sold, distributed or otherwise made available to and should not be offered, sold, distributed or otherwise made available to any retail investor in the United Kingdom. For these purposes, a "retail investor" means a person who is not a professional client, as defined in point (8) of Article 2(1) of Regulation (EU) No 600/2014 as it forms part of domestic law in the United Kingdom ("UK MiFIR"). Consequently, no disclosure document required by the FCA Product Disclosure Sourcebook ("DISC") for offering, selling or distributing the notes or otherwise making them available to retail investors in the United Kingdom has been prepared and therefore offering or selling the notes or otherwise making them available to any retail investor in the United Kingdom may be unlawful under DISC and the Consumer Composite Investments (Designated Activities) Regulations 2024.

UK MiFIR product governance / Professional investors and ECPs only target market - Solely for the purposes of the manufacturer's product approval process, the target market assessment in respect of the notes has led to the conclusion that: (i) the target market for the notes is only eligible counterparties, as defined in the FCA Handbook Conduct of Business Sourcebook, and professional clients, as defined in UK MiFIR; and (ii) all channels for distribution of the notes to eligible counterparties and professional clients are appropriate. Any person subsequently offering, selling or recommending the notes (a "distributor") should take into consideration the manufacturer's target market assessment; however, a distributor subject to the FCA Handbook Product Intervention and Product Governance Sourcebook is responsible for undertaking its own target market assessment in respect of the notes (by either adopting or refining the manufacturer's target market assessment) and determining appropriate distribution channels.

The communication of this pricing supplement, the accompanying prospectus supplement, the accompanying prospectus, any related free writing prospectus and any other document or materials relating to the issue of the notes offered hereby is not being made, and this pricing supplement, the accompanying prospectus supplement, the accompanying prospectus, any related free writing prospectus and such other documents and/or materials have not been approved, by an authorized person for the purposes of section 21 of the FSMA. Accordingly, this pricing supplement, the accompanying prospectus supplement, the accompanying prospectus, any related free writing prospectus and such other documents and/or materials are not being distributed to, and must not be passed on to, the general public in the United Kingdom. This pricing supplement, the accompanying prospectus supplement, the accompanying prospectus, any related free writing prospectus and such other documents and/or materials are for distribution only to persons who (i) have professional experience in matters relating to investments and who fall within the definition of investment professionals (as defined in Article 19(5) of the Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the "Financial Promotion Order")), (ii) fall within Article 49(2)(a) to (d) of the Financial Promotion Order, (iii) are outside the United Kingdom, or (iv) are other persons to whom it may otherwise lawfully be communicated or distributed under the Financial Promotion Order (all such persons together being referred to as "relevant persons"). This pricing supplement, the accompanying prospectus supplement, the accompanying prospectus, any related free writing prospectus and any such other documents and/or materials are directed only at relevant persons and must not be acted on or relied on by persons who are not relevant persons. Any investment or investment activity to which this pricing supplement, the accompanying prospectus supplement, the accompanying prospectus, any related free writing prospectus and any such other documents and/or materials relate will be engaged in only with relevant persons. Any person in the United Kingdom that is not a relevant person should not act or rely on this pricing supplement, the accompanying prospectus supplement, the accompanying prospectus, any related free writing prospectus or any other documents and/or materials relating to the issue of the notes offered hereby or any of their contents.

PS-2

PS-3

PS-4

Risk Factors

For a discussion of the risk factors affecting Morgan Stanley and its business, including market risk, credit risk, operational risk, liquidity risk, risk management strategies, models and processes, legal, regulatory and compliance risk, competitive environment, and other risks, see "Risk Factors" in Part I, Item 1A of our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 and our current and periodic reports filed pursuant to the Securities Exchange Act of 1934, as amended (file number 001-11758) that are incorporated by reference into this pricing supplement and the accompanying prospectus supplement and prospectus.

This section describes certain selected risk factors relating to the notes. Please see "Risk Factors" in the accompanying prospectus for a complete list of risk factors relating to the notes.

Early Redemption Risks

The notes have early redemption risk. In addition to the optional make-whole redemption discussed above under "-Other Provisions," we have the option to redeem the notes, (i) in whole but not in part, on June , 2029 or (ii) in whole at any time or in part from time to time, on or after May , 2030, on at least 3 business days' but not more than 60 calendar days' prior notice. It is more likely that we will redeem the notes prior to the stated maturity date to the extent that the interest payable on such notes is greater than the interest that would be payable on other instruments of ours of a comparable maturity, of comparable terms and of a comparable credit rating trading in the market. If the notes are redeemed prior to the stated maturity date, you may have to re-invest the proceeds in a lower interest rate environment.

Optional Redemption

In addition to the optional make-whole redemption discussed above under "-Other Provisions," we may, at our option, redeem the notes, (i) in whole but not in part, on June , 2029 or (ii) in whole at any time or in part from time to time, on or after May , 2030, on at least 3 business days' but not more than 60 calendar days' prior notice, at a redemption price equal to 100% of their principal amount, plus accrued and unpaid interest on the notes to but excluding the redemption date. If fewer than all of the notes are to be redeemed, the trustee will select, not more than 60 calendar days prior to the redemption date, the particular notes or portions thereof for redemption from the outstanding notes not previously called for redemption in accordance with its procedures at the time of selection; provided, that if the notes are represented by one or more global securities, beneficial interests in such notes will be selected for redemption by the applicable depositary in accordance with its standard procedures therefor.

On or before the redemption date, we will deposit with the trustee money sufficient to pay the redemption price of and accrued interest on the notes to be redeemed on that date. If such money is so deposited, on and after the redemption date interest will cease to accrue on such notes (unless we default in the payment of the redemption price and accrued interest) and such notes will cease to be outstanding.

For information regarding notices of redemption, see "Description of Debt Securities-Redemption and Repurchase of Debt Securities-Notice of Redemption" in the accompanying prospectus.

The notes do not contain any provisions affording the holders the right to require us to purchase the notes after the occurrence of any change in control event affecting us.

PS-5

United States Federal Taxation

In the opinion of our counsel, Davis Polk & Wardwell LLP, the notes should be treated as "variable rate debt instruments" denominated in a currency (the "denomination currency") other than the U.S. dollar for U.S. federal tax purposes, and should therefore be subject to special rules under Section 988 of the Internal Revenue Code of 1986, as amended, and the Treasury Regulations thereunder. See the discussion in the section of the accompanying prospectus supplement called "United States Federal Taxation―Tax Consequences to U.S. Holders― Notes Treated as Foreign Currency Notes" for further information about the treatment of the notes. Although there is uncertainty regarding their treatment (and subject to the discussion below regarding deemed exercise of our optional redemption right), the notes should be treated as providing for a single fixed rate followed by a single qualified floating rate ("QFR"), as described in the sections of the accompanying prospectus supplement called "United States Federal Taxation―Tax Consequences to U.S. Holders― Notes Treated as Variable Rate Debt Instruments―Interest on a VRDI That Provides for Multiple Rates." Under this treatment, in order to determine the amount of qualified stated interest ("QSI") and original issue discount ("OID") in respect of the notes, an equivalent fixed rate debt instrument (denominated in euro) must be constructed for the entire term of the notes. The equivalent fixed rate debt instrument is constructed in the following manner: (i) first, the initial fixed rate is converted to a QFR that would preserve the fair market value of the notes, and (ii) second, each QFR (including the QFR determined under (i) above) is converted to a fixed rate substitute (which should generally be the value of that QFR as of the issue date of the notes). Under Treasury Regulations applicable to certain options arising under the terms of a debt instrument, in determining the amount of QSI and OID, we should be deemed to exercise our optional redemption right if doing so would reduce the yield on the equivalent fixed rate debt instrument. For the purpose of determining QSI and OID, the optional make-whole redemption should not be deemed to be exercised. However, if, as of the issue date, redeeming the notes on June , 2029 would reduce the yield of the equivalent fixed rate debt instrument, the notes should be treated as fixed rate debt instruments maturing on June , 2029 (the "instrument maturing June 2029"). Under those circumstances, if the notes are not actually redeemed by us on June , 2029, solely for purposes of the OID rules, they should be deemed retired and reissued for their principal amount, and should thereafter be treated as floating rate debt instruments with a term of one year (the "1-year instrument"). The instrument maturing June 2029 would be treated as issued without OID, and all payments of interest thereon would be treated as QSI. Interest on the 1-year instrument should generally be taken into account when received or accrued, according to your method of tax accounting, but it is possible that the 1-year instrument could be subject to the rules described under "United States Federal Taxation―Tax Consequences to U.S. Holders―Notes Treated as Short-term Notes" in the accompanying prospectus supplement.

If, as of the issue date, redeeming the notes on June , 2029 would not reduce the yield on the equivalent fixed rate debt instrument, the rules under "United States Federal Taxation―Tax Consequences to U.S. Holders―General―Original Issue Discount" should be applied to the equivalent fixed rate debt instrument to determine the amounts of QSI and OID on the notes. Under those circumstances, the notes may be issued with OID.

A U.S. holder is required to include any QSI in income in accordance with the U.S. holder's regular method of accounting for U.S. federal income tax purposes. U.S. holders will be required to include any OID in income for U.S. federal income tax purposes as it accrues, in accordance with a constant yield method based on a compounding of interest. All amounts will be determined in the denomination currency and then translated into U.S. dollars according to the rules described in the section of the accompanying prospectus supplement called "United States Federal Taxation-Tax Consequences to U.S. Holders-Notes Treated as Foreign Currency Notes." QSI allocable to an accrual period must be increased (or decreased) by the amount, if any, which the interest actually accrued or paid during an accrual period (including the fixed rate payments made during the initial period) exceeds (or is less than) the interest assumed to be accrued or paid during the accrual period under the equivalent fixed rate debt instrument.

Both U.S. and non-U.S. holders of the notes should read the section of the accompanying prospectus supplement entitled "United States Federal Taxation."

You should consult your tax adviser regarding all aspects of the U.S. federal tax consequences of an investment in the notes, as well as any tax consequences arising under the laws of any state, local or non-U.S. taxing jurisdiction.

The discussion in the preceding paragraphs under "United States Federal Taxation," and the discussion contained in the section entitled "United States Federal Taxation" in the accompanying prospectus supplement, insofar as they purport to describe provisions of U.S. federal income tax laws or legal conclusions with respect thereto, constitute the full opinion of Davis Polk & Wardwell LLP regarding the material U.S. federal tax consequences of an investment in the notes.

PS-6

Supplemental Information Concerning Plan of Distribution; Conflicts of Interest

On June , 2026, we agreed to sell to the managers listed in this pricing supplement, and they severally agreed to purchase, the principal amounts of notes set forth opposite their respective names below at a net price of %, plus accrued interest, if any, which we refer to as the "purchase price" for the notes. The purchase price equals the stated issue price of %, plus accrued interest, if any, less a combined management and underwriting commission of % of the principal amount of the notes.

Morgan Stanley & Co. International plc ("MSIP") is our wholly-owned subsidiary.

MSIP is not a U.S. registered broker-dealer and, therefore, to the extent that it intends to effect any sales of the notes in the United States, it will do so through Morgan Stanley & Co. LLC ("MS & Co."). MS & Co. is our wholly-owned subsidiary. MS & Co. will conduct this offering in compliance with the requirements of Rule 5121 of the Financial Industry Regulatory Authority, Inc., which is commonly referred to as FINRA, regarding a FINRA member firm's distribution of the securities of an affiliate and related conflicts of interest. MS & Co. or any of our other affiliates may not make sales in this offering to any discretionary account without the prior written approval of the customer.