Middlesex School

The Board of Trustees' investment committee oversees the endowment. Its members include Juan Sabater, a partner and co-president at Valor Equity Partners, and Jasmine Richards, who leads diverse manager investing at Cambridge Associates. Dune Thorne, a trustee with experience on the Boston Museum of Fine Arts' investment committee, also contributes. Day-to-day management is typically delegated to an outsourced chief investment officer or investment staff, though no internal OCIO is publicly named.

The endowment holds approximately $220 million in total assets based on the most recent IRS filings (Altss estimate). The portfolio is structured across venture capital, buyout, and fund-of-funds commitments, with allocations spanning seed-stage to late-stage expansion. Physical campus assets, including the Clay Centennial Center and Bass Arts Pavilion, represent a separate store of value not counted within pooled investment holdings.

The endowment's investment strategy centers on fund commitments, not direct company investments. The committee members' backgrounds — including Juan Sabater's role sourcing direct deals at Valor Equity Partners — suggest the school could access co-investment opportunities, but its historical posture is as a limited partner in venture and buyout funds rather than a direct investor.

The endowment allocates to venture capital from seed through late-stage expansion, in addition to buyout and fund-of-funds strategies. Specific sector tilts are not publicly disclosed, but the trustee network's expertise leans toward enterprise technology and consumer platforms — Sabater's firm focuses on high-growth technology companies, while Richards' work at Cambridge Associates spans diverse emerging managers across multiple verticals.

The endowment supports the school's financial aid, faculty salaries, and campus maintenance alongside tuition revenue and annual giving. Middlesex has not disclosed a formal draw rate, but typical boarding-school endowments distribute 4–5% of assets annually. The school's 350-acre Concord campus represents additional non-investment assets that reduce reliance on endowment draws for capital projects.

The initial capital came from Frederick Winsor and a cohort of wealthy Boston families with ties to the Kidder, Peabody investment bank, including Robert Winsor, Francis Cabot Lowell, and Henry Lee Higginson. Subsequent growth has been fueled by donations from alumni, including Instagram co-founder Kevin Systrom, whose family is noted in school records, and multi-generational giving from legacy Boston families.

The endowment's trustee network is unusually concentrated in Boston's institutional investment community. Dune Thorne's dual role on the investment committees of both Middlesex School and the Boston Museum of Fine Arts creates overlap with a major regional allocator, while Juan Sabater's Valor Equity Partners ties link the school to a distinctive pipeline of direct technology deals. This local, relationship-driven sourcing differs from the consultant-led models common at peer boarding schools.