Jefferies Financial Group Inc美股招股说明书(2026-05-07版)

The information in this preliminary pricing supplement is not complete and may be changed without notice. This preliminary pricingsupplement is not an offer to sell these securities, nor a solicitation of an offer to buy these securities, in any jurisdiction where the offering isnot permitted. SUBJECT TO COMPLETION, DATED May 6, 2026 PRELIMINARY PRICING SUPPLEMENT(to Product Supplement no. 5, dated October 23, 2023, Prospectus Supplement dated May 12,2023 and Prospectus dated May 12, 2023) $Jefferies Jefferies Financial Group Inc.Senior Autocallable Barrier Notes due May 20, 2031 Linked to the Worst-Performing of the Russell 2000® Index, the S&P 500® Index and the Dow Jones Industrial Average® The Senior Autocallable Barrier Notes due May 20, 2031 Linked to the Worst-Performing of the Russell 2000® Index,the S&P 500® Index and the Dow Jones Industrial Average® (the “Notes”) are seniorunsecured obligations of Jefferies Financial Group Inc.The Notes have the terms described in the accompanying product supplement, prospectus supplement and prospectus, as supplemented ormodified by this pricing supplement.The Notes are issued as part of our Series A Global Medium-Term Notes program. All payments are subject to our credit risk.If we default on our obligations, you could lose some or a significant portion of your investment.These Notes are not secured obligations andyou will not have any security interest in, or otherwise have any access to, any Underlying or the securities represented by any Underlying.SUMMARY OF TERMS The worst-performing of the Russell 2000® Index (the “RTY”), the S&P 500® Index (the “SPX”) and the Dow Jones Industrial Average®(the “INDU”).Please see“The Underlyings” below. Autocallable Notes. The Notes will be automatically called if the Observation Value of the Worst-Performing Underlying on any Call Observation Date (beginningapproximately one year after the Pricing Date) is equal to or greater than its Call Value.If your Notes are called, you will receive the applicable Call Payment onthe applicable Call Payment Date, and no further amounts will be payable on the Notes.The Stated Principal Amountplusthe applicable Call Premium. The Call Premium applicable to each Call Observation Date is set forth on page PS-2 and reflects a return of approximately 13.30% per annum. The Notes are“Snowball Coupon Notes” for purposes of the accompanying product supplement and, for purposes of this pricing supplement, references in the accompanyingproduct supplement to “Snowball Coupon Payment” shall be deemed to refer to “Call Premium”.If the Notes are not called prior to maturity and the Final Value of the Worst-Performing Underlying is greater than or equal to its Threshold Value,you will receive for each Note that you hold a Payment at Maturity that is equal to the Stated Principal AmountIf the Notes are not called prior to maturity and the Final Value of the Worst-Performing Underlying is less than its Threshold Value, you will receive for each Note that you hold a Payment at Maturity that is less than the Stated Principal Amount of each Note that will equal: Jefferies LLC, the broker-dealer subsidiary of Jefferies Financial Group Inc., is a member of FINRA and will participate in the distribution of the notes being offeredhereby.Accordingly, the offering is subject to the provisions of FINRA Rule 5121 relating to conflicts of interest and will be conducted in accordance with therequirements of Rule 5121.See “Conflict of Interest.”The Notes will be our senior unsecured obligations and will rank equally with our other senior unsecured indebtedness. 1 An affiliate of the Issuer will pay a structuring fee of up to $6.50 per Note in connection with the distribution of the Notes to other registered broker-dealers.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 product supplement, prospectus or prospectus supplement is truthful or complete.Any representation to the contrary is a criminal offense.As used in this pricing supplement,“we,”“us”and“our”refer to Jefferies Financial Group Inc., unless the context requires otherwise.We will deliver the Notes in book-entry form only through The Depository Trust Company on or about May 20, 2026 against payment in immediately available funds.Jefferies Pricing supplement dated , 2026.You should read this pricing supplement together with the related product supplement, prospectus and prospectus supplement, each of which can be accessed via thehyperlinks below, before you decide to invest.Product Supplement no. 5 dated October 23, 2023Prospectus supplement dated May 12, 2023 and Prospectus dated May 12, 2023 PRICING SUPPLEMENT SPECIAL NOTE ON FORWARD-LOOKING STATEMENTSPS-iiTHE NOTESPS-1HOW THE NOTES WORKPS-4RISK FACTORSPS-5THE UNDERLYINGSPS-10HEDGINGPS-18SUPPLEMENTAL DISCUSSION OF U.S. FEDERAL INCOME TAX CONSEQUENCE