Rowley Law PLLC is investigating potential securities law violations by Columbia Banking System, Inc. (NASDAQ: COLB) and its board of directors concerning the proposed acquisition of the company by Umpqua Holdings Corporation (NASDAQ: UMPQ). Columbia Banking System stockholders are expected to own approximately 38% of the combined company. The transaction is expected to close in mid-2022.

If you are a stockholder of Columbia Banking System, Inc. and are interested in obtaining additional information regarding this investigation, please fill in the contact form on this page. You may also contact Shane Rowley, Esq. at Rowley Law PLLC, 50 Main Street Suite 1000, White Plains, NY 10606, by email at, or by telephone at 914-400-1920 or 844-400-4643 (toll-free).

Rowley Law PLLC represents shareholders nationwide in class actions and derivative lawsuits in complex corporate litigation.

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