SEC Form FWP filed by Jefferies Financial Group Inc.

Free Writing Prospectus

(to the Preliminary Prospectus Supplement dated July 7, 2026 and Prospectus dated May 11, 2026)

July 8, 2026

Filed Pursuant to Rule 433

Registration Statement No. 333-295759

Jefferies Financial Group Inc.

4.500% SENIOR NOTES DUE 2033

* A securities rating is not a recommendation to buy, sell or hold securities and may be subject to revision or withdrawal at any time.

** The Notes will be ready for delivery in book-entry form only on or about July 15, 2026, which is the fifth business day following the date of pricing of the Notes (such settlement cycle being referred to as “T+5”). You should be advised that trading of the Notes may be affected by the T+5 settlement. Under the E.U. Central Securities Depositaries Regulation, trades in the secondary market generally are required to settle in two business days in the place of settlement unless the parties to such trade expressly agree otherwise. Under Rule 15c6-1 under the Exchange Act, trades in the secondary market generally are required to settle in one business day unless the parties to any such trade expressly agree otherwise. Accordingly, purchasers who wish to trade the Notes prior to the date that is one business day preceding the settlement date will be required, by virtue of the fact that the Notes initially will settle in T+5, to specify an alternative settlement cycle at the time of any such trade to prevent failed settlement. Purchasers of the Notes who wish to trade the Notes during such period should consult their own advisor.

MiFID II and UK MiFIR – professionals/ECPs only / no EEA PRIIPs KID or UK CCI product summary – Manufacturer target market (MiFID II and UK MiFIR product governance) is eligible counterparties and professional clients only (all distribution channels). No EEA PRIIPs KID and no UK CCI product summary has been prepared as the Notes are not available to retail investors in the EEA or the UK.

The Issuer has filed a registration statement (including a prospectus and a prospectus supplement) with the Securities and Exchange Commission (“SEC”) for the offering to which this communication relates. Before you invest, you should read the prospectus in that registration statement, the prospectus supplement relating to this offering and other documents that the Issuer has filed with the SEC for more complete information about the Issuer and such offering. You may get these documents for free by visiting EDGAR on the SEC website at www.sec.gov. Alternatively, the Issuer or any underwriter or dealer participating in the offering will arrange to send you the prospectus supplement relating to this offering if you request it  by contacting Jefferies International Limited, by calling toll-free at (877) 877-0696 or by emailing DCMProspectuses@jefferies.com; or Banco Santander, S.A. at 34-91-257-2029, or by email at syndicate@gruposantander.com; or Citigroup Global Markets Limited toll-free at 1-800-831-9146, or by email at prospectus@citi.com; or Natixis at 1-866-425-1819, or by email at legal.bonds@natixis.com; or SMBC Bank International plc at +44 (0)20 4507 1000, or by email at GBLOSecuritiesLegal@gb.smbcgroup.com; or Société Générale at +33 (0)1 42 13 32 16, or by email at eur-glba-syn-cap@sgcib.com.

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