Jefferies Financial Group Inc美股招股说明书(2026-06-18版)

PRELIMINARY PRICING SUPPLEMENT(to Prospectus Supplement dated May 11, 2026 and Prospectus datedMay 11, 2026) $Jefferies Jefferies Financial Group Inc.Senior Callable Floating Rate Range Accrual Notes Linked to the 10-Year CMT Rate due June 30, 2031 We have the right to redeem the Notes, in whole or in part, on each Optional Redemption Date. Subject to our redemption right, interest will accrue and be payable monthly, in arrears, from,and including, the Original Issue Date to, but excluding, the stated maturity date (June 30, 2031), at a variable rate per annum equal to (a) the Contingent Rate of 7.50% per annum times(b) the quotient ofNdivided byD, whereN= the number of calendar days during the applicable Interest Payment Period on which the Accrual Provision (defined below) is satisfied andD=the total number of calendar days in such Interest Payment Period. All payments on the Notes, including the repayment of principal, are subject to the credit risk of Jefferies Financial GroupInc. SUMMARY OF TERMS Issuer:Title of the Notes:Aggregate Principal Amount:Issue Price: Jefferies Financial Group Inc. Senior Callable Floating Rate Range Accrual Notes Linked to the 10-Year CMT Rate due June 30, 2031$. We may increase the Aggregate Principal Amount prior to the Original Issue Date but are not required to do so. At variable prices. The Notes will be offered at a price equal to 100% of the Stated Principal Amount per Note until the initial pricing date,which is, 2026. Thereafter, the Notes will be offered from time to time in one or more negotiated transactions at varying prices to bedetermined at the time of each sale, which may be at market prices prevailing, at prices related to such prevailing prices or at negotiatedprices, subject to a maximum price of 100% of the Stated Principal Amount per Note.$1,000 per Note June, 2026June 30, 2026 (Business Days after the Pricing Date)June 30, 2031, subject to our redemption right.June 30, 2026 Stated Principal Amount:Pricing Date:Original Issue Date:Maturity Date:Interest Accrual Date:Payment at Maturity:10-Year CMT Rate: The Payment at Maturity per Note will be the Stated Principal Amount plus accrued and unpaid interest, if any. With respect to any Accrual Determination Date, the yield for United States Treasury securities at “constant maturity” with a designatedmaturity of 10 years, determined as set forth under “The Notes” below. Interest Rate: From and including the Original Issue Date to, but excluding, June 30, 2031: For each Interest Payment Period, a variable rate per annumequal to (i) the Contingent Rate times (ii) the quotient ofNdivided byD, whereN= the number of calendar days during the applicableInterest Payment Period on which the Accrual Provision is satisfied andD= the total number of calendar days in such Interest PaymentPeriod. The Interest Rate applicable to each Interest Payment Period will not be greater than 7.50% per annum or less than 0.00% perannum.It is possible that you could receive little or no interest on the Notes. For each Interest Payment Period, the Accrual Provision shall be deemed to have been satisfied for each calendar day during such InterestPayment Period on which the 10-Year CMT Rate, as determined on the Accrual Determination Date relating to such calendar day, is lessthan or equal to 5.00%. If the 10-Year CMT Rate, as determined on the Accrual Determination Date relating to such calendar day, is greaterthan 5.00%, then the Accrual Provision shall be deemed not to have been satisfied for such calendar day. Accrual Provision: With respect to any calendar day during an Interest Payment Period that is also a U.S. Government Securities Business day, such calendarday. With respect to any calendar day during an Interest Payment Period that is not also a U.S. Government Securities Business Day, theimmediately prior U.S. Government Securities Business Day. Notwithstanding the foregoing, for all calendar days in the Exclusion Period, theAccrual Determination Date will be the first U.S. Government Securities Business Day that precedes such Exclusion Period. The AccrualProvision will be deemed to have not been satisfied for the calendar days during the Exclusion Period if the 10-Year CMT Rate is greaterthan 5.00% on the first U.S. Government Securities Business Day that precedes such Exclusion Period.For each Interest Payment Period, the period commencing on the fourth business day prior to but excluding the Interest Payment Date for Accrual Determination Date: Exclusion Period: such Interest Payment Period. Contingent Rate:Interest Payment Period: 7.50% per annum Monthly (from and including the 30th calendar day of each month to, but excluding, the 30th calendar day of the immediately following month,beginning June 30, 2026; provided that any Interest Payment Period which begins or ends in February will begin or end on the last calendarday of such month, as applicable) The 30th calendar day of each month, beginning