CB Increases Regular Cash Dividend

Columbia Banking System Increases Regular Cash Dividend;
Declares Special Cash Dividend

Columbia Banking System, Inc. announced that a quarterly cash dividend of $0.09 per common share will be paid on August 22, 2012 to shareholders of record as of the close of business on August 8, 2012. This is a 13% increase from $0.08 per share paid in the prior three quarters.

In addition, the Board of Directors declared a special cash dividend of $0.21 per common share, which will also be paid on August 22, 2012 to shareholders of record as of the close of business on August 8, 2012.

Melanie Dressel, President and Chief Executive Officer noted, “Our ongoing commitment is to actively manage our capital position. In light of our strong capital levels and second quarter earnings, we are pleased to pay a special cash dividend. Along with our regular dividend, this constitutes a full payout of earnings for the quarter.”