Jefferies Financial Group Inc. 美股招股说明书（2026年3月3日版）

Filed pursuant to Rule 424(b)(2)Registration No. 333-271881 The information in this preliminary pricing supplement is not complete and may be changed without notice. This preliminary pricing supplement is not an offer tosell these securities, nor a solicitation of an offer to buy these securities, in any jurisdiction where the offering is not permitted.PRELIMINARY PRICING SUPPLEMENTSUBJECT TO COMPLETION, DATED March 3, 2026 Jefferies Financial Group Inc. Senior Fixed Rate 5 Year Callable Notes due March 17, 2031We have the right to redeem the Notes, in whole or in part, on each Optional Redemption Date. Subject to our redemption right, the amount of interest payable on the Notes will be 5.00%from and including the Original Issue Date to, but excluding, the stated maturity date (March 17, 2031). All payments on the Notes, including the repayment of principal, are subject to thecredit risk of Jefferies Financial Group Inc. SUMMARY OF TERMS Jefferies Financial Group Inc. Optional Redemption Dates:Specified Currency:CUSIP/ISIN:Book-entry or Certificated Note:Business Day: 47233WMB2 / US47233WMB27 (1) The Agent may purchase the Notes for sale to certain fee-based advisory accounts and may forgo some or all of their underwriting discounts and commissions. The price for investorspurchasing the Notes in these accounts will be reduced by an amount that will be up to such forgone underwriting discounts and commissions. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this pricingsupplement or the accompanying prospectus or either prospectus supplement is truthful or complete. Any representation to the contrary is a criminal offense.We will deliver the Notes in book-entry form only through The Depository Trust Company on or about March 17, 2026 against payment in immediately available funds. JefferiesPricing supplement dated You should read this document together with the related prospectus and prospectus supplement,each of which can be accessed via the hyperlinks below, before you decide to invest.Prospectus supplement dated May 12, 2023 and Prospectus dated May 12, 2023 You should rely only on the information contained in or incorporated by reference in this pricing supplement and theaccompanying prospectus and prospectus supplements. We have not authorized anyone to provide you with differentinformation. We are not making an offer of these securities in any state where the offer is not permitted. You should notassume that the information contained in this pricing supplement or the accompanying prospectus is accurate as of any date Table of Contents SPECIAL NOTE ON FORWARD-LOOKING STATEMENTS This pricing supplement and the accompanying prospectus and prospectus supplement contain or incorporate by reference “forward-looking statements” within the meaning of the safe harbor provisions of Section 27A of the Securities Act of 1933 (the “Securities Act”)and Section 21E of the Securities Exchange Act of 1934. These forward-looking statements are not statements of historical fact andrepresent only our belief as of the date such statements are made. There are a variety of factors, many of which are beyond our control,which affect our operations, performance, business strategy and results and could cause actual reported results and performance todiffer materially from the performance and expectations expressed in these forward-looking statements. These factors include, but arenot limited to, financial market volatility, actions and initiatives by current and future competitors, general economic conditions, controls Table of Contents THE NOTES The Notes offered are our debt securities. We describe the basic features of these Notes in the sections of the accompanyingprospectus called “Description of Securities We May Offer—Debt Securities” and the prospectus supplement called “Description of If any Interest Payment Date, any Optional Redemption Date or the Maturity Date occurs on a day that is not a Business Day, then thepayment owed on such date will be postponed until the next succeeding Business Day. No additional interest will accrue on the Notes “30/360 (ISDA)” means the number of days in the Interest Payment Period in respect of which payment is being made divided by 360,calculated on a formula basis as follows, as described in Section 4.16(f) of the 2006 ISDA Definitions published by the InternationalSwaps and Derivatives Association, without regard to any subsequent amendments or supplements: where: “Y1” is the year, expressed as a number, in which the first day of the Interest Payment Period falls; “Y2” is the year, expressed as a number, in which the day immediately following the last day included in the Interest PaymentPeriod falls; “M1” is the calendar month, expressed as a number, in which the first day of the Interest Payment Period falls; “M2” is the calendar month, expressed as a number,