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): June 27, 2023 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 8.01    Other Events On June 27, 2023, Frost Bank, the principal operating subsidiary of Cullen/Frost Bankers, Inc., issued a press release announcing plans for a major expansion that will double the number of financial centers in the area of Austin, Texas. A copy of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated by reference into this Item 8.01. Item 9.01    Financial Statements and Exhibits (d)   Exhibits: 99.1    Press Release. 104    Cover Page Interactive Data File - The cover page XBRL tags are 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.     CULLEN/FROST BANKERS, INC.      By:     /s/ Jerry Salinas             Jerry Salinas         Group Executive Vice President         and Chief Financial Officer     Dated:    June 27, 2023 EXHIBIT INDEX Exhibit Number Description    99.1 Press Release. 104 Cover Page Interactive Data File - The cover page XBRL tags are embedded within the inline XBRL document.