On February 15, 2013, Cullen/Frost Bankers, Inc. (the "Company") issued and sold 6,000,000 shares of 5.375% Non-Cumulative Perpetual Preferred Stock, Series A, par value $0.01 and liquidation preference $25 per share ("Series A Preferred Stock"). Under the terms of the Series A Preferred Stock, the ability of the Company to declare or pay dividends on, or purchase, redeem or otherwise acquire, shares of its common stock or any securities of the Company that rank junior to the Series A Preferred Stock is subject to certain restrictions in the event that the Company does not declare and pay dividends on the Series A Preferred Stock for the most recent dividend period. The terms of the Series A Preferred Stock, including such restrictions, are more fully described in the Certificate of Designations, filed with the Office of the Secretary of State of the State of Texas on February 13, 2013 (the "Certificate of Designations"), a copy of which is filed as Exhibit 3.3 to the Company's Registration Statement on Form 8-A filed on February 15, 2013 and is incorporated herein by reference.

The Certificate of Designations establishes the preferences, limitations and relative rights of the Series A Preferred Stock. The Certificate of Designations became effective upon filing, and a copy of the Certificate of Designations is filed as Exhibit 3.3 to the Company's Registration Statement on Form 8-A filed on February 15, 2013 and is incorporated herein by reference.

On February 12, 2013, the Company entered into an underwriting agreement (the "Underwriting Agreement") with Morgan Stanley & Co. LLC, Goldman, Sachs & Co. and UBS Securities LLC, as representatives of the several underwriters listed therein, relating to the public offering of the Series A Preferred Stock. A copy of the Underwriting Agreement is being filed as Exhibit 1.1 hereto and is incorporated herein by reference. This Current Report on Form 8-K is being filed for the purpose of filing the Underwriting Agreement as an exhibit to the Company's registration statement on Form S-3 (File No. 333-186335) (the "Registration Statement") and such exhibit is incorporated herein by reference to the Registration Statement.

A copy of the opinion of Stanley E. McCormick, Jr., Executive Vice President, Corporate Counsel and Secretary of the Company, is attached as Exhibit 5.1 to this Current Report on Form 8-K. Exhibits 3.1, 5.1 and 23.1 to this Current Report on Form 8-K are incorporated herein by reference to the Registration Statement.

(d) Exhibits.

Exhibit No.                                  Description

1.1               Underwriting Agreement, dated February 12, 2013, by and among
                  Cullen/Frost Bankers, Inc., Morgan Stanley & Co. LLC, Goldman,
                  Sachs & Co. and UBS Securities LLC, as representatives of the
                  several underwriters listed therein.

3.1               Certificate of Designations of Cullen/Frost Bankers, Inc., filed
                  with the Office of the Secretary of State of the State of Texas
                  and effective February 13, 2013 (filed as Exhibit 3.3 to the
                  Company's Form 8-A filed on February 15, 2013 and incorporated by
                  reference herein).

5.1               Opinion of Stanley E. McCormick, Jr.

23.1              Consent of Stanley E. McCormick, Jr. (included in Exhibit 5.1).