Westamerica Bancorporation is a bank holding company. The Company provides a range of banking services to individual and commercial customers in Northern and Central California through its subsidiary bank, Westamerica Bank (the Bank). The communities served are located in Northern and Central California, from Mendocino, Lake and Nevada Counties in the north to Kern County in the south. It provides a range of loans, including commercial loans, commercial real estate loans, real estate construction loans, residential real estate loans and consumer installment and other loans. The Company maintains an investment securities portfolio consisting of securities issued by United States Government sponsored entities, agency and non-agency mortgage-backed securities, state and political subdivisions, corporations, collateralized loan obligations, commercial paper and other securities.