NEW YORK--(BUSINESS WIRE)-- #creditratingagency--KBRA assigns a rating of A- with a Stable Outlook to the $250 million subordinated notes issued by Columbia Bank ("the bank") with a final maturity date of September 18, 2036. The notes are callable at the option of the bank, commencing on September 18, 2031. Net proceeds will be used for general corporate purposes and to retire trust preferred securities outstanding at its holding company, Columbia Banking System, Inc. (NASDAQ: COLB). Key Credit Considerations The ra.