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 Date of Report (Date of earliest event reported): April 29, 2026 Cullen/Frost Bankers, Inc. (Exact name of registrant as specified in its charter) Texas 001-13221 74-1751768 (State or other jurisdiction of incorporation or organization) (Commission File Number) (I.R.S. Employer Identification No.) 111 W. Houston Street, San Antonio, Texas 78205 (Address of principal executive offices) (Zip code) (210) 220-4011 (Registrant's telephone number, including area code) N/A (Former name, former address and former fiscal year, 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 Stock, $.01 Par Value CFR New York Stock Exchange Depositary Shares, each representing a 1/40th interest in a share of 4.450% Non-Cumulative Perpetual Preferred Stock, Series B CFR.PrB 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 5.07 Submission of Matters to a Vote of Security Holders At the Annual Meeting of Shareholders of the Company held on April 29, 2026, shareholders voted on the following matters: (1) To elect fourteen Director nominees to serve on the Board of Directors of the Company for a one-year term that will expire at the 2027 Annual Meeting of Shareholders. Final voting results were as follows: Name of Nominee Votes For Votes Against Abstentions Broker Non-Votes Hope Andrade 51,978,882  523,317  111,181  6,451,057  Anthony R. Chase 51,435,150  1,043,371  134,859  6,451,057  Cynthia J. Comparin 51,708,705  792,323  112,352  6,451,057  Samuel G. Dawson 51,957,106  538,830  117,444  6,451,057  Crawford H. Edwards 52,221,785  274,860  116,735  6,451,057  John T. Engates 52,167,597  316,657  129,126  6,451,057  Phillip D. Green 51,742,031  784,648  86,701  6,451,057  David J. Haemisegger 51,585,394  900,229  127,757  6,451,057  Charles W. Matthews 50,362,468  1,872,037  378,875  6,451,057  Joseph A. Pierce 51,763,247  720,473  129,660  6,451,057  Jeffrey M. Rummel 52,267,841  207,457  138,082  6,451,057  Linda B. Rutherford 51,765,683  724,340  123,357  6,451,057  Marsha M. Shields 52,224,659  273,628  115,093  6,451,057  Jack Willome 51,932,140  531,430  149,810  6,451,057  (2) To provide nonbinding approval of executive compensation. Final voting results were as follows: Votes For 50,928,898  Votes Against 1,530,796  Abstentions 153,686  Broker Non-Votes 6,451,057  (3) To ratify the selection of Ernst & Young LLP to act as independent auditors of the Company for the fiscal year that began January 1, 2026. Final voting results were as follows: Votes For 57,710,536  Votes Against 1,237,323  Abstentions 116,578  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.     CULLEN/FROST BANKERS, INC. By: /s/ Daniel J. Geddes   Daniel J. Geddes   Group Executive Vice President and Chief Financial Officer   (Duly Authorized Officer, Principal Financial Officer) Dated: April 29, 2026 3