PacWest Bancorp is a bank holding company with one wholly owned banking subsidiary, Pacific Western Bank. The bank has tens of full-service branches mostly located throughout California. The bank provides commercial banking services, including real estate, construction, and commercial loans, as well as comprehensive deposit and treasury management services, to small and midsize businesses. The bank also offers additional products and services targeting established middle-market and entrepreneurial businesses under the brands of its business groups, CapitalSource and Square 1 Bank, respectively. About a third of the bank's loan portfolio is concentrated in commercial real estate mortgages. The vast majority of the bank's net revenue comes from net interest income.