Selective Insurance Group, Inc.

Item 5.02. Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers. On September 16, 2026, the Board of Directors (the “Board”) of Selective Insurance Group, Inc. (the “Company”) increased the size of the Board from 12 members to 13 members and appointed Wole C. Coaxum as a non-employee director of the Company, effective September 16, 2026 (the “Appointment”). The Board also named Mr. Coaxum to the Board’s Audit Committee and Compensation and Human Capital Committee. Mr. Coaxum previously served on the Board from 2020 to 2025. Mr. Coaxum’s term will continue until the Company’s 2027 Annual Meeting of Stockholders or until his successor has been duly elected and qualified. Mr. Coaxum will receive the same compensation and benefits as the other non-employee directors on the Board, consistent with the Company’s non-employee director compensation program described in the Definitive Proxy Statement on Schedule 14A (at pages 77 to 79) that the Company filed with the Securities and Exchange Commission on March 26, 2026. However, Mr. Coaxum will not receive an annual equity award for fiscal year 2026, as the Company’s 2026 Annual Meeting of Stockholders, at which time the annual equity awards were granted, was already held. Mr. Coaxum’s annual cash retainer for fiscal year 2026 will be prorated for the period from the Appointment through December 31, 2026. No arrangements or understandings exist between Mr. Coaxum or any other persons by which he was named a director of the Company. Mr. Coaxum has no family relationships with any Company director or executive officer, and the Company has not entered into any transactions with Mr. Coaxum reportable per Item 404(a) of Regulation S-K. Item 7.01. Regulation FD Disclosure. On September 16, 2026, the Company issued a press release regarding the Appointment, a copy of which is attached hereto as Exhibit 99.1 and incorporated herein by reference. The information in Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.1, is being furnished and shall not be deemed “filed” for the purpose or liabilities of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as expressly set forth by specific reference in any filing. The Company makes no admission about the materiality of any information in this report or the attached exhibits. Important information may be disseminated initially or exclusively via the Company’s corporate website, www.selective.com/investors. Investors should consult the site to access this information. Any website addresses included herein are inactive textual references only. The information contained on any such website referenced herein is not incorporated into this Current Report on Form 8-K. Item 9.01. Financial Statements and Exhibits. (d) Exhibits Exhibit No. Description of Exhibit ────────────────────────────────────────────────────────────────────────────────────────────────── 99.1 Press Release of Selective Insurance Group, Inc. dated September 16, 2026 104 The cover page from this Current Report on Form 8-K, formatted in Inline XBRL

Item 7.01. Regulation FD Disclosure. On September 16, 2026, the Company issued a press release regarding the Appointment, a copy of which is attached hereto as Exhibit 99.1 and incorporated herein by reference. The information in Item 7.01 of this Current Report on Form 8-K, including Exhibit 99.1, is being furnished and shall not be deemed “filed” for the purpose or liabilities of Section 18 of the Securities Exchange Act of 1934, as amended, nor shall it be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, except as expressly set forth by specific reference in any filing. The Company makes no admission about the materiality of any information in this report or the attached exhibits. Important information may be disseminated initially or exclusively via the Company’s corporate website, www.selective.com/investors. Investors should consult the site to access this information. Any website addresses included herein are inactive textual references only. The information contained on any such website referenced herein is not incorporated into this Current Report on Form 8-K.