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): November 14, 2025 UNUM GROUP (Exact name of registrant as specified in its charter) Delaware 001-11294 62-1598430 (State or other jurisdiction of incorporation) (Commission File Number) (IRS Employer Identification No.) 1 Fountain Square Chattanooga , Tennessee 37402 (Address of principal executive offices) (Zip Code) ( 423 ) 294-1011 (Registrant's telephone number, including area code) Not Applicable (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 ( see General Instruction A.2. below): ☐ 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 stock, $0.10 par value   UNM   New York Stock Exchange 6.250% Junior Subordinated Notes due 2058 UNMA New York Stock Exchange Indicate by check mark whether the registrant is an emerging growth company as defined in 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 November 14, 2025, Unum Group, a Delaware corporation ( “ Unum Group ” or the “ Company ” ), announced that it had completed an offering of $300,000,000 aggregate principal amount of 5.250% Senior Notes due 2035 (the “ Notes ” ). The Notes were offered and sold pursuant to an Underwriting Agreement, dated November 6, 2025 (the “ Underwriting Agreement ” ), and issued by the Company under an Indenture, dated as of August 23, 2012, as amended by the First Supplemental Indenture, dated as of August 20, 2020. Copies of the Underwriting Agreement, the form of the Notes, the opinion of Sullivan & Cromwell LLP, special counsel to the Company, relating to the validity of the Notes, and a news release concerning the offering of the Notes are attached hereto as Exhibits 1.1, 4.1, 5.1 and 99.1, respectively. The Notes were offered and sold under the Company ’ s effective registration statement on Form S-3 (File No. 333-271511) filed with the U.S. Securities and Exchange Commission (the “ SEC ” ). The Company has filed with the SEC a prospectus supplement, dated November 6, 2025, together with the accompanying base prospectus, dated April 28, 2023, relating to the offer and sale of the Notes. Item 9.01      Financial Statements and Exhibits. (d) Exhibits.    The following exhibits are filed with this report: Exhibit No. Description 1.1 Underwriting Agreement, dated November 6, 2025, with respect to the Notes, between Unum Group and Goldman Sachs & Co. LLC, PNC Capital Markets LLC, U.S. Bancorp Investments, Inc. and Wells Fargo Securities, LLC, as representatives of the several underwriters named in Schedule II thereto. 4.1 Form of 5.250% Senior Notes due 2035. 5.1 Opinion of Sullivan & Cromwell LLP, dated November 14, 2025, as to the validity of the Notes. 23.1 Consent of Sullivan & Cromwell LLP (included in Exhibit 5.1). 99.1 News release of Unum Group, dated November 14, 2025, concerning the offering of the Notes. 104 Cover Page Interactive Data File (embedded with the Inline XBRL document). 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. Unum Group (Registrant) Date: November 14, 2025 By: /s/ J. Paul Jullienne Name: J. Paul Jullienne Title: Vice President, Managing Counsel, and Corporate Secretary