Shareholder Vote

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 May 12, 2026 Date of Report: (Date of earliest event reported) __________________________ ARTHUR J. GALLAGHER & CO. (Exact name of registrant as specified in its charter) __________________________ Delaware 1-09761 36-2151613 (State or other jurisdiction of incorporation or organization) (Commission File Number) (I.R.S. Employer Identification Number) 2850 Golf Road , Rolling Meadows , Illinois 60008 , (630) 773-3800 (Address, including zip code and telephone number, including area code, of registrant’s principal executive offices) 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: o Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425) o Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12) o Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b)) o 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, $1.00 par value AJG 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 5.07.          Submission of Matters to a Vote of Security Holders Arthur J. Gallagher & Co. (the “ Company ”) held its Annual Meeting of Stockholders on May 12, 2026 (the “ Annual Meeting ”). At the Annual Meeting, the Company’s stockholders (i) elected all nine director nominees, whose names appear below, to serve until the Company’s 2027 Annual Meeting of Stockholders, (ii) approved the ratification of the appointment of Ernst & Young LLP as the Company’s Independent Registered Public Accounting Firm for the fiscal year ending December 31, 2026 (“ Auditor Ratification ”), and (iii) approved, on a non-binding advisory basis, the Company’s named executive officers’ compensation (“ Say-on-Pay ”). The final voting results are set forth below: Election of Directors For Against Abstain Broker Non-Votes Deborah Caplan 211,513,060 7,202,894 362,383 17,728,311 Teresa Clarke 218,062,809 769,246 246,282 17,728,311 John Coldman 217,116,946 1,634,326 327,065 17,728,311 Richard Harries 217,583,019 1,085,307 410,011 17,728,311 Pat Gallagher 210,660,653 8,259,296 158,388 17,728,311 David Johnson 209,086,172 8,450,616 1,541,549 17,728,311 Chris Miskel 196,557,440 21,836,322 684,575 17,728,311 Ralph Nicoletti 215,380,816 3,204,733 492,788 17,728,311 Norman Rosenthal 214,403,981 4,201,669 472,687 17,728,311 For Against Abstain Auditor Ratification 225,670,790 9,793,375 1,342,483 For Against Abstain Broker Non-Votes Say-on-Pay 200,825,370 18,035,501 217,466 17,728,311 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. Arthur J. Gallagher & Co. Date: May 13, 2026 By: /s/ Walter D. Bay Walter D. Bay Vice President, General Counsel and Secretary