Passco Companies also provides investment advisory services, leasing, asset and property management, construction management, and brokerage as well as property development, development and disposition, and construction and management services. Founded in 1998 by William O. Passo, Passco Companies is headquartered in Irvine, California, and currently has $3.9 billion assets under management across the country, with a focus on growing its portfolio in primary and secondary markets throughout the United States.