Westamerica Bancorporation operates as a bank holding company for the Westamerica Bank that provides various banking products and services to individual and commercial customers.

The company accepts various deposit products, including retail savings and checking accounts, as well as certificates of deposit.

Its loan portfolio includes commercial, commercial and residential real estate, real estate construction, and consumer installment loans, as well as indirect automobile loans.

The company was formerly known as Independent Bankshares Corporation and changed its name to Westamerica Bancorporation in 1983.

The company was founded in 1884 and is headquartered in San Rafael, California.