Castilleja School Foundation

Castilleja School Foundation

Founded in 1907, Castilleja School Foundation is the non-profit entity supporting Castilleja School, a non-sectarian all-girls middle and high school in Palo Alto. The school's real estate footprint, built by the late Silicon Valley developer John Arrillaga, anchors the endowment's physical assets and ties it to one of Northern California's legendary real estate families. Laura Arrillaga-Andreessen, a former trustee and the daughter of John Arrillaga, represents the connective tissue between the school and the valley's philanthropic elite, while funder support from The Sobrato Organization's John A. Sobrato Sr. and the Arrillaga Family Foundation historically underwrites campus expansion and capital campaigns. The endowment's investment strategy is not publicly documented as a discrete asset allocation, but the composition of its board reveals the sourcing funnel. The finance committee includes Raj Agrawal, who leads infrastructure at KKR, and Chi-Hua Chien, co-founder of Goodwater Capital, a consumer-tech venture firm. This points to an investment committee comfortable with venture and growth equity, likely alongside fund commitments to managers drawn from the personal networks of its trustees. The foundation maintains a direct real estate portfolio of campus and residential properties along Bryant Street, Emerson Street, and Melville Avenue in downtown Palo Alto, plus municipal bond exposure in California. The physical campus modernization, including an underground parking garage completed in recent years, doubles as a long-term, yield-bearing commercial asset in one of the world's most supply-constrained housing markets. With an estimated $179 million in assets (Altss estimate), the foundation operates with a lean, non-professionalized investment staff, steering capital through its volunteer trustee board. There are no adjacent multi-family office vehicles or disclosed co-investment clubs. The model mirrors that of many elite independent school endowments — a small pool of capital levered to the calling networks of a powerful board — but amplified by its Palo Alto zip code and the sheer density of technology wealth among its 115-year alumnae base. What distinguishes the Castilleja Foundation structurally is the asymmetry between its modest nominal endowment and the latent capital its governance board could call in a campaign. The board is stacked with senior leaders from Meta, KKR, Venrock, Goodwater Capital, and Menlo Equities — a group capable of writing small checks from the endowment's core and sourcing enormous follow-on co-investment when needed. The foundation does not face the disclosure or pacing pressures of a university endowment, yet it functions as a quiet allocation hub for a strand of valley wealth that rarely shows up in LP databases.