摩根士丹利美股招股说明书(2026-01-23版)

Subject to Completion, Preliminary Pricing Supplement dated January 22, 2026 PROSPECTUS Dated April 12, 2024PRODUCT SUPPLEMENT Dated November 16, 2023INDEX SUPPLEMENT Dated November 16, 2023 Pricing Supplement No. 13,631 toRegistration Statement Nos. 333-275587;333-275587-01Dated, 2026 Morgan Stanley Finance LLC STRUCTURED INVESTMENTSOpportunities in U.S. Equities $ Digital S&P 500®Index-Linked Notes dueFully and Unconditionally Guaranteed by Morgan Stanley Principal at Risk Securities The notesare unsecured obligations of Morgan Stanley Finance LLC (“MSFL”) and are fully and unconditionallyguaranteed by Morgan Stanley. The notes will not bear interest.The amount that you will be paid on your notes onthe stated maturity date (expected to be the second scheduled business day after the determination date) is based on the performance of the S&P 500®Index as measured from the trade date to and including the determination date (expected tobe between 13 and 15 months after the trade date). If the final underlier level on the determination date is greater than orequal to 85% of the initial underlier level (which will be set on the trade date and may be higher or lower than the actualclosing level of the underlier on the trade date), you will receive an amount equal to the maximum settlement amount All payments are subject to our credit risk. If we default on our obligations, you could lose some or all of yourinvestment. These notes are not secured obligations and you will not have any security interest in, or otherwisehave any access to, any underlying reference asset or assets. To determine your payment at maturity, we will calculate the underlier return, which is the percentage increase or decreasein the final underlier level from the initial underlier level. On the stated maturity date, for each $1,000 face amount of yournotes, you will receive an amount in cash equal to: ●if the underlier return isgreater thanorequal to-15% (the final underlier level is greater than or equal to 85% of theinitial underlier level), the maximum settlement amount of $1,066.90 to $1,078.50 per note, or 106.69% to 107.85% ofthe face amount (the actual maximum settlement amount will be determined on the trade date); or●if the underlier return isless than-15% (the final underlier level is less than 85% of the initial underlier level), thesumof (i)$1,000plus(ii)theproductof (a)$1,000times(b)approximately 1.1765times(c)thesumof the underlier returnplus15%. You should read the additional disclosure herein so that you may better understand the terms and risks of your investment. The estimated value on the trade date will be approximately $981.70 per note, or within $15.00 of thatestimate. See “Estimated Value” on page 2. (2)See “Additional Information About the Notes—Use of proceeds and hedging” beginning on page 19. The notes involve risks not associated with an investment in ordinary debt securities. See “Risk Factors”beginning on page 10. The Securities and Exchange Commission and state securities regulators have not approved or disapproved these notes, ordetermined if this document or the accompanying product supplement, index supplement and prospectus is truthful or complete. Anyrepresentation to the contrary is a criminal offense. The notes are not deposits or savings accounts and are not insured by the Federal Deposit Insurance Corporation or any othergovernmental 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 beaccessed via the hyperlinks below. When you read the accompanying product supplement and index supplement, please note that allreferences in such supplements to the prospectus dated November 16, 2023, or to any sections therein, should refer instead to theaccompanying prospectus dated April 12, 2024 or to the corresponding sections of such prospectus, as applicable. Please also see About Your Prospectus The notes are notes issued as part of MSFL’s Series A Global Medium-Term Notes program. This prospectusincludes this preliminary pricing supplement and the accompanying documents listed below. This preliminarypricing supplement constitutes a supplement to the documents listed below and should be read in conjunction ●Prospectus dated April 12, 2024●Product Supplement dated November 16, 2023●Index Supplement dated November 16, 2023 When you read the accompanying product supplement and index supplement, please note that all referencesin such supplements to the prospectus dated November 16, 2023, or to any sections therein, should referinstead to the accompanying prospectus dated April 12, 2024 or to the corresponding sections of suchprospectus, as applicable. The information in this preliminary pricing supplement supersedes any conflictinginformation in the documents listed above. In addition, some of the terms or features described in the listed