Company Update

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): April 23, 2026 Jefferies Financial Group Inc. (Exact name of registrant as specified in its charter) New York 001-05721 13-2615557 (State or other jurisdiction of incorporation) (Commission File Number) (IRS Employer Identification No.) 520 Madison Ave. , New York , New York   10022 (Address of principal executive offices)   (Zip Code) Registrant’s telephone number, including area code: 212 - 284-2300 (Former name or former address, if changed since last report.) Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions: ☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) ☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) ☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) ☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c)) Securities registered pursuant to Section 12(b) of the Act: Title of each class   Trading Symbol(s)   Name of each exchange on which registered           Common Shares, par value $1 per share   JEF   New York Stock Exchange 4.850% Senior Notes Due 2027   JEF 27A   New York Stock Exchange 5.875% Senior Notes Due 2028   JEF 28   New York Stock Exchange 2.750% Senior Notes Due 2032   JEF 32A   New York Stock Exchange 6.200% Senior Notes Due 2034   JEF 34   New York Stock Exchange 5.500% Senior Notes Due 2036   JEF36   New York Stock Exchange Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). Emerging growth company ☐ If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐ Item 8.01. Other Events. On April 23, 2026, Jefferies Financial Group Inc. issued a press release (the “Pricing Press Release”) announcing the pricing of its public offering of $1,100,000,000 aggregate principal amount of 5.125% Senior Notes due 2031. A copy of the Pricing Press Release is attached hereto as Exhibit 99.1 and is incorporated herein by reference. Item 9.01. Financial Statements and Exhibits (d) Exhibits. Number Exhibit     99.1 Pricing Press Release, dated April 23, 2026     104 Cover Page Interactive Data File (embedded within the Inline XBRL document) 2 SIGNATURES Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Date: April 23, 2026 JEFFERIES FINANCIAL GROUP INC.       /s/ Michael J. Sharp   Michael J. Sharp   Executive Vice President and General Counsel 3