PacWest Bancorp is a bank holding company with one wholly-owned banking subsidiary, Pacific Western Bank. Pacific Western provides commercial banking services, including real estate, construction, and commercial loans, and deposit and treasury management services to small and medium-sized businesses. It offers additional products and services under the brands of its business groups, CapitalSource and Square 1 Bank. CapitalSource provides cash flow, asset-based, equipment and real estate loans and treasury management services to established middle-market businesses on a national basis. Square 1 Bank focuses on entrepreneurial businesses and their venture capital and private equity investors.