杰弗里金融集团股份有限公司美国存托凭证招股说明书（2026年6月24日版）

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 June 24, 2026 PRELIMINARY PRICING SUPPLEMENT(to Product Supplement no. 5, dated May 11, 2026, Prospectus Supplement dated May 11, 2026and Prospectus dated May 11, 2026) Jefferies Jefferies Financial Group Inc.Senior Autocallable Contingent Coupon Barrier Notes due July 8, 2032 Linked to the Worst-Performing of the Nasdaq-100 Index®, the Russell 2000®Index and the VanEck® If 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 isless than the Stated Principal Amount of each Note that will equal: Jefferies LLC, a wholly-owned subsidiary of Jefferies Financial Group Inc. See “Supplemental Plan of Distribution.”Jefferies Financial Services, Inc., a wholly owned subsidiary of Jefferies Financial Group Inc. Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this pricing supplement or theaccompanying 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 July 8, 2026 against payment in immediately available funds. You should read this pricing supplement together with the related product supplement, prospectus and prospectus supplement, each of which can be accessed via the hyperlinks below,before you decide to invest.Product Supplement No. 5 dated May 11, 2026Prospectus Supplement dated May 11, 2026 and Prospectus dated May 11, 2026 You should rely only on the information contained in or incorporated by reference in this pricing supplement and theaccompanying product supplement, prospectus and prospectus supplement. We have not authorized anyone to provide youwith different information. We are not making an offer of these securities in any state where the offer is not permitted. Youshould not assume that the information contained in this pricing supplement or the accompanying product supplement, SPECIAL NOTE ON FORWARD-LOOKING STATEMENTS This pricing supplement and the accompanying product supplement, prospectus and prospectus supplement contain or incorporate byreference “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 ofhistorical fact and represent only our belief as of the date such statements are made. There are a variety of factors, many of which arebeyond our control, which affect our operations, performance, business strategy and results and could cause actual reported resultsand performance to differ materially from the performance and expectations expressed in these forward-looking statements. Thesefactors include, but are not limited to, financial market volatility, actions and initiatives by current and future competitors, generaleconomic conditions, controls and procedures relating to the close of the quarter, the effects of current, pending and future legislation or THE NOTES The Notes are senior unsecured obligations of Jefferies Financial Group Inc. The Aggregate Principal Amount of the Notes is $The Notes will mature on July 8, 2032. The Notes have the terms described in the accompanying product supplement, prospectus supplement and prospectus, as supplemented or modified by this pricing supplement. The Notes will pay a Contingent CouponPayment of $16.08 on the applicable Coupon Payment Date if the Observation Value of the Worst-Performing Underlying on theapplicable monthly Coupon Observation Date is greater than or equal to its Coupon Barrier. The Notes will be automatically called if theObservation Value of the Worst-Performing Underlying on any Call Observation Date (beginning approximately six months after thePricing Date) is equal to or greater than its Call Value. If your Notes are called, you will receive the Call Payment on the applicable CallPayment Date, and no further amounts will be payable on the Notes. If your Notes are not called, at maturity, if the Final Value of the The Stated Principal Amount of each Note is $1,000. The Issue Price will equal 100% of the Stated Principal Amount per Note. Thisprice includes costs associated with issuing, selling, structuring and hedging the Notes, which are borne by you, and, consequently, theestimated