杰弗瑞斯金融集团股份有限公司美股招股说明书(2025-09-19版)

The information in this preliminary pricing supplement is not complete and may be changed. This preliminary pricing supplement and theaccompanying product supplement, prospectus supplementandprospectus are not an offer to sell these securities and we are not solicitingan offer to buy these securities in any jurisdiction where the offer or sale is not permitted. Subject To Completion, dated September 19, 2025 PRELIMINARY PRICING SUPPLEMENT dated September 19, 2025(To Product Supplement No. 2 dated June 30, 2023Prospectus Supplement dated May 12, 2023and Prospectus dated May 12, 2023)Jefferies Financial Group Inc. Medium-Term Notes, Series A Market Linked Securities—Auto-Callable with Contingent Coupon and Contingent Downside Principal at Risk Securities Linked to the Lowest Performing of the S&P 500®Index, the Russell 2000®Indexand the EURO STOXX 50®Index due October 1, 2029■Linked to the lowest performing of the S&P 500®Index, the Russell 2000®Index and the EURO STOXX 50® Index (each referred to asan “Index”)■Unlike ordinary debt securities, the securities do not provide for fixed payments of interest, do not repay a fixed amount of principal at stated maturity and are subject to potential automatic call prior to stated maturity upon the terms described below. Whether the securitiespay a contingent coupon, whether the securities are automatically called prior to stated maturity and, if they are not automatically called,whether you receive the face amount of your securities at stated maturity will depend, in each case, on the closing level of the lowestperforming Index on the relevant calculation day. The lowest performing Index on any calculation day is the Index that has the lowestclosing level on that calculation day as a percentage of its starting level■Contingent Coupon.The securities will pay a contingent coupon on a quarterly basis until the earlier of stated maturity or automatic call if, and only if, the closing level of the lowest performing Index on the calculation day for that quarter is greater than or equal to itsthreshold level. However, if the closing level of the lowest performing Index on a calculation day is less than its threshold level, you willnot receive any contingent coupon for the relevant quarter. If the closing level of the lowest performing Index is less than its thresholdlevel on every calculation day, you will not receive any contingent coupons throughout the entire term of the securities. The thresholdlevel for each Index is equal to 75% of its starting level. The contingent coupon rate will be determined on the pricing date and will be atleast 9.25% per annum■Automatic Call.If the closing level of the lowest performing Index on any of the quarterly calculation days from March 2026 to June 2029, inclusive, is greater than or equal to its starting level, the securities will be automatically called for the face amount plus a finalcontingent coupon payment■Potential Loss of Principal.If the securities are not automatically called prior to stated maturity, you will receive the face amount at stated maturity if,and only if, the closing level of the lowest performing Index on the final calculation day is greater than or equal to itsthreshold level. If the closing level of the lowest performing Index on the final calculation day is less than its threshold level, you will losemore than 25%, and possibly all, of the face amount of your securities.■If the securities are not automatically called prior to stated maturity, you will have full downside exposure to the lowest performing Index from its starting level if its closing level on the final calculation day is less than its threshold level, but you will not participate in anyappreciation of any Index and will not receive any dividends on securities included in any Index■Your return on the securities will depend solely on the performance of the Index that is the lowest performing Index on each calculation day. You will not benefit in any way from the performance of the better performing Indices. Therefore, you will be adversely affected if anyIndex performs poorly, even if the other Indices perform favorably■All payments on the securities are subject to our credit risk, and you will have no ability to pursue any securities included in any Index for payment; if we default on our obligations under the securities, you could lose some or all of your investment■No exchange listing; designed to be held to maturity We estimate that the value of each security on the pricing date will be approximately $960.50, or within $30.00 of that estimate.Our estimate of thevalue of the securities as determined on the pricing date will be set forth in the final pricing supplement. See “Estimated Value of the Securities” inthis pricing supplement.The securities have complex features and investing in the securities involves risks not associated with an investment in conventional debt securities. See “Selected Risk Considerations” beginning on