[FWP] Morgan Stanley Free Writing Prospectus

Rhea-AI Filing Summary

Morgan Stanley Finance LLC, fully guaranteed by Morgan Stanley, is offering SPUMP40 Contingent Income Memory Buffered Auto-Callable Securities due July 16, 2030. The notes are linked to the S&P U.S. Equity Momentum 40% VT 4% Decrement Index (ticker SPUMP40).

Key commercial terms:

• Contingent coupon: at least 9.0% per annum, paid monthly, with a memory feature if the index closes ≥70% of its initial level on the relevant observation date.
• Automatic early redemption: monthly, starting after the first year, if the index closes at or above 90% of its initial level; investors then receive 100% principal plus accrued coupon.
• Downside exposure: a 15% buffer protects principal for index declines up to 15%. Below that, investors lose 1% of principal for each percentage point decline beyond the buffer, with a maximum loss of 85%.
• Estimated value: approximately $906 versus the $1,000 issue price, reflecting structuring and hedging costs.
• No listing; secondary liquidity will be limited and prices may be volatile.

Primary risks highlighted include (i) no participation in any index appreciation, (ii) reliance on Morgan Stanley’s credit, (iii) potential early redemption that caps income stream, (iv) the index’s limited operating history and 4% decrement drag, (v) uncertain U.S. tax treatment, and (vi) model-based valuation that may differ from secondary market pricing.

Positive

• At least 9% annual contingent coupon with memory feature provides attractive income potential.
• 15% downside buffer offers limited principal protection against moderate market declines.
• Monthly auto-call feature at 90% of initial level can return capital early with accrued coupon.
• Guarantee from Morgan Stanley parent may enhance perceived credit strength versus standalone issuers.

Negative

• Estimated value of $906 vs. $1,000 issue price signals an immediate economic drag of roughly 9.4%.
• No upside participation; maximum redemption is par, capping total return to coupons received.
• Credit risk: payments depend on Morgan Stanley’s ability to pay, not on collateral.
• Illiquidity risk: securities will not be exchange-listed; secondary trading may be limited.
• Underlying index is new (incepted 2022) and employs a 4% decrement, increasing model and performance uncertainty.
• Potential loss up to 85% if index declines beyond the 15% buffer at maturity.

Insights

Structured Products Analyst

TL;DR: High coupon and 15% buffer attractive, but limited upside, credit risk and 9% value discount temper appeal.

The 9% memory coupon, monthly observations and 90% call threshold make these notes competitive for income-seeking investors willing to accept equity risk. The 15% buffer is standard for five-year notes and shields against moderate market pullbacks. However, upside is capped at par, so total return relies entirely on coupons. The estimated value of $906 indicates roughly 9.4% in fees and hedging costs at issuance, an immediate economic drag. With no exchange listing, exit liquidity and pricing transparency are limited. Because the underlying SPUMP40 index is new, uses leverage and a 4% decrement, historical analysis is thin, adding model risk. Overall, risk-reward skews neutral: appealing carry, but notable structural and credit risks.

Risk Analyst

TL;DR: Novel index, credit exposure and illiquidity elevate downside; buffer only partial protection.

Investors face Morgan Stanley senior unsecured credit risk for up to five years. If spreads widen, secondary prices could fall irrespective of index moves. The 15% buffer still allows an 85% loss in severe markets, and coupons stop if the index breaches the 70% barrier. Monthly auto-call at 90% may shorten duration, reinvestment risk arises if markets recover early. The index’s leverage and decrement methodology introduce tracking uncertainty versus traditional benchmarks, while its inception date of March 2022 limits stress-tested data. Given these factors, the instrument is suitable only for investors with a strong credit view on Morgan Stanley and comfort with structured-note liquidity constraints.

Free Writing Prospectus to Preliminary Pricing Supplement No. 9,171

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

Dated July 1, 2025; Filed pursuant to Rule 433

Morgan Stanley

SPUMP40 Contingent Income Memory Buffered Auto-Callable Securities due July 16, 2030

This document provides a summary of the terms of the securities. Investors must carefully review the accompanying preliminary pricing supplement referenced below, product supplement, index supplement and prospectus, and the “Risk Considerations” on the following page, prior to making an investment decision.

Terms
Issuer:	Morgan Stanley Finance LLC
Guarantor:	Morgan Stanley
Underlier:	S&P® U.S. Equity Momentum 40% VT 4% Decrement Index (SPUMP40)
Automatic early redemption:	If, on any redemption determination date, the closing level of the underlier is greater than or equal to the call threshold level, the securities will be automatically redeemed. No further payments will be made on the securities once they have been automatically redeemed.
Call threshold level:	90% of the initial level
Redemption determination dates:	Beginning after 1 year, monthly
Contingent coupon:	At least 9.00% per annum, with a memory feature. See the accompanying preliminary pricing supplement.
Coupon payment dates:	Monthly
Coupon barrier level:	70% of the initial level
Buffer amount:	15% (85% maximum loss)1
Pricing date:	July 11, 2025
Final observation date:	July 11, 2030
Maturity date:	July 16, 2030
CUSIP:	61778NFQ9
Estimated value:	$906.00 per security, or within $55.00 of that estimate
Preliminary pricing supplement:	https://www.sec.gov/Archives/edgar/data/895421/000183988225036017/ms9171_424b2-19698.htm
1All payments are subject to our credit risk

Hypothetical Payment at Maturity1 (if the securities have not been automatically redeemed)
% Change in Closing Level of the Underlier	Payment at Maturity per Security (excluding any contingent coupon payable at maturity)
+100.00%	$1,000.00
+80.00%	$1,000.00
+60.00%	$1,000.00
+40.00%	$1,000.00
+20.00%	$1,000.00
0.00%	$1,000.00
-10.00%	$1,000.00
-15.00%	$1,000.00
-16.00%	$990.00
-20.00%	$950.00
-40.00%	$750.00
-60.00%	$550.00
-80.00%	$350.00
-100.00%	$150.00

The issuer has filed a registration statement (including a prospectus) with the SEC for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement and other documents the issuer has filed with the SEC for more complete information about the issuer and this offering. You may get these documents for free by visiting EDGAR on the SEC Web site at www.sec.gov. Alternatively, the issuer, any underwriter or any dealer participating in the offering will arrange to send you the prospectus if you request it by calling toll-free 1-800-584-6837.

Underlier(s)

For more information about the underlier(s), including historical performance information, see the accompanying preliminary pricing supplement.

Risk Considerations

The risks set forth below are discussed in more detail in the “Risk Factors” section in the accompanying preliminary pricing supplement. Please review those risk factors carefully prior to making an investment decision.

Risks Relating to an Investment in the Securities

●The securities provide for only the minimum payment at maturity.

●The securities do not provide for the regular payment of interest.

●Payment of the contingent coupon is based on the closing level of the underlier on only the related observation date at the end of the related interest period.

●Investors will not participate in any appreciation in the value of the underlier.

●The securities are subject to early redemption risk.

●The market price of the securities may be influenced by many unpredictable factors.

●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.

●As a finance subsidiary, MSFL has no independent operations and will have no independent assets.

●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.

●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.

●The securities will not be listed on any securities exchange and secondary trading may be limited.

●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.

Risks Relating to the Underlier(s)

●Because your return on the securities will depend upon the performance of the underlier, the securities are subject to the following risks, as discussed in more detail in the accompanying index supplement. The accompanying index supplement refers to the underlier as the “Index.”

oNo assurance can be given that the investment strategy used to construct the Index will achieve its intended results or that the Index will be successful or will outperform any alternative index or strategy that might reference the Index Components.

oThe decrement of 4% per annum will adversely affect the performance of the Index in all cases, whether the Index appreciates or depreciates.

oThe Index is subject to risks associated with the use of significant leverage.

oThe Index may not be fully invested.

oThe Index was established on March 14, 2022 and therefore has very limited operating history.

oAs the Index is new and has very limited historical performance, any investment in the Index may involve greater risk than an investment in an index with longer actual historical performance and a proven track record.

oHigher future prices of the futures contract to which the Index is linked relative to its current prices may adversely affect the value of the Index and the value of instruments linked to the Index.

oSuspensions or disruptions of market trading in futures markets could adversely affect the price of instruments linked to the Index.

oLegal and regulatory changes could adversely affect the return on and value of your securities.

oThe E-mini Russell 2000 futures contracts are one of the Index Components and are subject to risks associated with small-capitalization companies.

oAdjustments to the Index could adversely affect the value of instruments linked to the Index.

Risks Relating to Conflicts of Interest

●The calculation agent, which is a subsidiary of Morgan Stanley and an affiliate of MSFL, will make determinations with respect to the securities.

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

Tax Considerations

You should review carefully the discussion in the accompanying preliminary pricing supplement under the caption “Additional Information About the Securities–United States federal income tax considerations” concerning the U.S. federal income tax consequences of an investment in the securities, and you should consult your tax adviser.

FAQ

What coupon rate do the Morgan Stanley SPUMP40 notes pay?

The notes pay a contingent coupon of at least 9.0% per annum, credited monthly when the index closes at or above 70% of its initial level.

When can the securities be automatically redeemed?

Starting 12 months after issue, the notes are auto-called on any monthly determination date if the index is ≥90% of its initial level.

How much principal protection does the 15% buffer provide?

At maturity, investors are protected against index declines of up to 15%; losses begin only for declines beyond that threshold.

What happens if the index is below the 70% coupon barrier on a payment date?

No coupon is paid for that period, but missed coupons may be recovered later under the memory feature if the barrier is subsequently met.

Why is the estimated value $906 per $1,000 note?

The estimate reflects issuer costs and hedging; these reduce the note’s fair value relative to the issue price, creating an initial valuation discount.

Do the notes trade on an exchange?

No. They are not listed; any resale must occur through the dealer network, which may result in limited liquidity and wider bid-ask spreads.