Results of Operations

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): January 30, 2020   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 5.375% Non-Cumulative Perpetual Preferred Stock, Series A   CFR.PRA   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 2.02    Results of Operations and Financial Condition Attached as Exhibit 99.1 and incorporated into this item by reference is a press release issued by the Registrant on January 30, 2020 regarding its financial results for the quarter and year ended December 31, 2019 . The information furnished by the Registrant pursuant to this item shall not be deemed “filed” for purposes of Section 18 of the Securities Exchange Act of 1934, or otherwise subject to the liability of that section, and shall not be deemed to be incorporated by reference into any filing under the Securities Act of 1933 or the Securities Exchange Act of 1934. Item 9.01    Financial Statements and Exhibits (d)   Exhibits: 99.1 Press Release dated January 30, 2020 with respect to the Registrant's financial results for the quarter and year ended December 31, 2019 . 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:     January 30, 2020 EXHIBIT INDEX Exhibit Number   Description          99.1   Press Release dated January 30, 2020 with respect to the Registrant's financial results for the quarter and year ended December 31, 2019. 104   Cover Page Interactive Data File - The cover page XBRL tags are embedded within the inline XBRL document.