Jefferies Financial Group Inc美股招股说明书(2026-05-28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 27, 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 June 2, 2028 Linked to the Worst-Performing of the iShares® U.S. Medical Devices ETF and the S&P 500®The Senior Autocallable Contingent Coupon Barrier Notes due June 2, 2028 Linked to the Worst-Performing of the iShares® U.S. Medical Devices ETF and the S&P 500®Index (the “Notes”) are senior unsecured obligations of Jefferies Financial Group Inc. The Notes have the terms described in the accompanying product supplement, prospectus supplement andprospectus, as supplemented or modified 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 Title of the Notes: Aggregate Principal Amount:Issue Price:Stated Principal Amount:Strike Date:Pricing Date:Original Issue Date:Coupon Observation Dates: Monthly, beginning on June 29, 2026, as set forth on page PS-2. The Coupon Observation Dates are subject to postponement as describedin the accompanying product supplement.As set forth on page PS-2. The Coupon Payment Dates may be postponed if the related Coupon Observation Date is postponed as described in the accompanying product supplement.Monthly, beginning on May 27, 2027, as set forth on page PS-2. The Call Observation Dates are subject to postponement as described in the Coupon Payment Dates: Call Observation Dates: accompanying product supplement.As set forth on page PS-2. The Call Payment Dates may be postponed if the related Call Observation Date is postponed as described in the Call Payment Dates: accompanying product supplement.May 30, 2028, subject to postponement as described in the accompanying product supplement. Valuation Date:Maturity Date:Underlying: June 2, 2028, which may be postponed if the Valuation Date is postponed as described in the accompanying product supplement. The worst-performing of the iShares® U.S. Medical Devices ETF (the “IHI”) and the S&P 500®Index (the “SPX”). Please see “The Underlyings” below.The Underlying with the lowest Observation Value or Final Value, as applicable, as compared to its Initial Value. Worst-Performing Underlying:Coupon Feature: Contingent Coupon Payments. The Notes will pay a Contingent Coupon Payment of $7.50 on the applicable Coupon Payment Date if theObservation Value of the Worst-Performing Underlying on the applicable monthly Coupon Observation Date is greater than or equal to itsCoupon Barrier.Autocallable Notes. The Notes will be automatically called if the Observation Value of the Worst-Performing Underlying on any Call Call Feature: Call Payment:Payment at Maturity: The Stated Principal Amount plus any Contingent Coupon Payment that may otherwise be due on the applicable Call Payment Date.If the Final Value of the Worst-Performing Underlying is greater than or equal to its Threshold Value, you will receive for each Notethat you hold a Payment at Maturity that is equal to the Stated Principal AmountIf 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: In this scenario the Payment at Maturity will be less than the Stated Principal Amount and you could lose some or all of your investment.The Payment at Maturity will also include the final Contingent Coupon Payment if the Observation Value of the Worst-Performing Underlyingon the final Coupon Observation Date is greater than or equal to its Coupon Barrier.$50.37 with respect to the IHI; and 7,519.12 with respect to the SPXWith respect to theIHI, the ETF Closing Price of the Underlyingtimesthe Adjustment Factor on the applicable Coupon Observation Date or Initial Value:Observation Value: Call Observation Date.With respect to theSPX, the Index Closing Value of the Underlying on the applicable Coupon Observation Date or Call Observation Date. With respect to theIHI, the ETF Closing Price of the Underlyingtimesthe Adjustment Factor on the Valuation Date. Final Value: With respect to theSPX, the Index Closing Value of the Underlying on the Valuation Date.$32.74 with respect to the IHI (65% of its Initial Value, rounded to two decimal places); and 4,887.43 with respect to the SPX (65% of its Initial Coupon Barri