On January 24, 2018, Ruben M. Escobedo notified Cullen/Frost Bankers, Inc. (Cullen/Frost) of his decision not to stand for re-election to the board of directors of Cullen/Frost (the board) when his term expires at Cullen/Frost's 2018 annual meeting of shareholders on April 25, 2018. Mr. Escobedo is the chairperson of Cullen/Frost's audit committee and is also a member of the compensation and benefits committee and the corporate governance and nominating committee. Also on January 24, 2018, R. Denny Alexander notified Cullen/Frost of his decision not to stand for re-election to the board when his term expires at the annual meeting on April 25, 2018. Mr. Alexander is a member of the wealth advisors committee of Frost Bank and has also served on the strategic planning committee of Cullen/Frost.