Bylaw Amendment

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 20, 2024 RLI Corp. (Exact name of registrant as specified in its charter) ​ ​ ​ ​ ​ ​ Delaware ​ 001-09463 ​ 37-0889946 (State or other jurisdiction ​ (Commission ​ (IRS Employer of incorporation) ​ File Number) ​ Identification No.) ​ ​ ​ ​ ​ 9025 North Lindbergh Drive , Peoria , IL ​ 61615 (Address of principal executive offices) ​ (Zip Code) ​ Registrant’s telephone number, including area code: ( 309 ) 692-1000 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: ☐ 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 Securities Exchange Act of 1934: ​ ​ ​ ​ ​ ​ Title of each class      Trading Symbol      Name of each exchange on which registered Common Stock $0.01 par value ​ RLI ​ 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 5.03    Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year ​ As previously announced on November 7, 2024, the Board of Directors of RLI Corp. (the “Company”) authorized a 2-for-1 forward split (the “Stock Split”) of its common stock, par value $0.01 per share (the “Common Stock”), to be effected through the filing of a Certificate of Amendment to the Company’s Amended and Restated Certificate of Incorporation (the “Certificate of Amendment”). The Certificate of Amendment, which the Company filed on November 20, 2024, will become effective at 5:00 p.m., Eastern Time, on January 15, 2025, and is filed as Exhibit 3.1 to this Current Report on Form 8-K. ​ The Certificate of Amendment will effect the Stock Split and also proportionately increase the number of shares of authorized Common Stock from 200,000,000 to 400,000,000. The two-for-one stock split is for shareholders of record as of December 31, 2024, and will be effective and shares distributed after the close of business on January 15, 2025. Trading in the Common Stock is expected to commence on a split-adjusted basis on January 16, 2024. ​ Item 9.01 Financial Statements and Exhibits. (d) Exhibits ​ Exhibit No.      Description ​ ​ ​ 3.1 ​ Certificate of Amendment to the Amended and Restated Certificate of RLI Corp., effective as of January 15, 2025 . 104 ​ Cover Page Interactive Data File (embedded within 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. ​ ​ ​ ​ ​ RLI CORP. ​ ​ ​ Date: November 20, 2024 By: /s/ Jeffrey D. Fick ​ ​ Jeffrey D. Fick ​ Chief Legal Officer & Corporate Secretary ​ ​ ​