杰弗里斯金融集团股份有限公司美股招股说明书（2025-10-29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 soliciting anoffer to buy these securities in any jurisdiction where the offer or sale is not permitted. Subject To Completion, dated October 29, 2025PRELIMINARY PRICING SUPPLEMENT dated October 29, 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 with Memory Feature andContingent Downside Principal at Risk Securities Linked to the Lowest Performing of the Common Stock of Lockheed Martin Corporation, the CommonStock of The Boeing Company and the Common Stock of General Dynamics Corporation due November 2, 2028■Linked to the lowest performing of the common stock of Lockheed Martin Corporation, the common stock of The Boeing Company and the common stock of General Dynamics Corporation (each referred to as an “Underlying Stock”)■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 securities pay a contingent coupon, whetherthe securities are automatically called prior to stated maturity and, if they are not automatically called, whether you receive the face amount of yoursecurities at stated maturity will depend, in each case, on the stock closing price of the lowest performing Underlying Stock on the relevant calculationday. The lowest performing Underlying Stock on any calculation day is the Underlying Stock that has the lowest stock closing price on that calculationday as a percentage of its starting price■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 stock closing price of the lowest performing Underlying Stock on the calculation day for that quarter is greater than or equal to its threshold price. Ifthe stock closing price of the lowest performing Underlying Stock on a calculation day is less than its threshold price, you will not receive any contingentcoupon on the related contingent coupon payment date. However, if the stock closing price of the lowest performing Underlying Stock on one or morecalculation days is less than its threshold price and, on a subsequent calculation day, the stock closing price of the lowest performing Underlying Stockon that subsequent calculation day is greater than or equal to its threshold price, the securities will pay the contingent coupon payment due for thatsubsequent calculation day plus all previously unpaid contingent coupon payments (without interest on amounts previously unpaid). If the stock closingprice of the lowest performing Underlying Stock on a calculation day is less than its threshold price and the stock closing price of the lowest performingUnderlying Stock on each subsequent calculation day up to and including the final calculation day is less than its threshold price, you will not receive theunpaid contingent coupon payments in respect of those calculation days. If the stock closing price of the lowest performing Underlying Stock is less thanits threshold price on every calculation day, you will not receive any contingent coupons throughout the entire term of the securities. The threshold pricefor each Underlying Stock is equal to 70% of its starting price. The contingent coupon rate will be determined on the pricing date and will be at least12.70% per annum■Automatic Call.If the stock closing price of the lowest performing Underlying Stock on any of the calculation days from April 2026 to July 2028, inclusive, is greater than or equal to its starting price, the securities will be automatically called for the face amount plus a final contingent couponpayment and any previously unpaid contingent coupon payments■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 stock closing price of the lowest performing Underlying Stock on the final calculation day is greater than or equal to its threshold price. Ifthe stock closing price of the lowest performing Underlying Stock on the final calculation day is less than its threshold price, you will lose more than 30%,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 Underlying Stock from its starting price if its stock closing price on the final calculation day is less than it