Columbia Banking System operates as the bank holding company for Columbia State Bank that provides a range of banking services to small and medium-sized businesses, professionals, and individuals. It offers personal and business banking products and services, including various types of lending and deposits, and treasury management services. In addition, the Company provides wealth management services in the areas of private banking, professional banking, financial services, and trust and estate services. Further, it offers fiduciary, agency, trust, and related services, as well as life insurance products.