Endowment / Foundation

Updated:

Moriah Fund

The Moriah Fund was established in 1985 by Robert and Clarence Efroymson, channeling the family's Midwestern retail and real estate fortune into what became a...

Moriah Fund logo

Moriah Fund

The Moriah Fund was established in 1985 by Robert and Clarence Efroymson, channeling the family's Midwestern retail and real estate fortune into what became a dual-purpose vehicle: a traditional Tikkun Olam grantmaker alongside a direct-venture portfolio generating returns to replenish the grants budget. Mary Ann Stein, Robert's daughter and Gideon's mother, served as founding president for 34 years before stepping into the chairwoman emerita role upon her death in 2023. The foundation operates from a single floor at 57 Warren Street in Tribeca. The fund's investment posture is unusual for a private foundation its size. Rather than outsourcing to external managers, Moriah directly deploys into venture capital — confirmed through a strategy classification spanning multiple general venture exposures and a portfolio footprint that includes the commercial asset Argyle Holdings LLC in Northern Manhattan. The geographic aperture is dual-track: domestic US real assets and venture stakes sit alongside a grantmaking program focused on civic engagement, education, and women's rights in the US, Israel, and globally. The foundation does not publicly disclose portfolio names, but its internal designation as a venture investor across six distinct strategy tags suggests a diversified direct-startup book rather than a fund-of-funds model. The foundation's scale is lean: roughly $72 million in assets, run by a tight family-governance structure with Gideon Stein as president, Dorothy Stein as secretary, and no publicly listed investment staff beyond the board. Mary Ann Stein's death in 2023 triggered a generational transition in both leadership and likely portfolio oversight. Adjacent to Moriah, the family maintains the Efroymson Family Fund — a separate philanthropic vehicle — and has left its mark on the Midwest through the Efroymson Family Entrance Pavilion at the Indianapolis Museum of Art. The family's network footprint extends through Mary Ann Stein's long presidencies at the New Israel Fund and Americans for Peace Now, and through Robert Stein's founding role at Democracy Alliance — connections that shaped Moriah's grantmaking partnerships but appear separate from its investment decision-making. What distinguishes Moriah structurally is its endowment-as-VC strategy: rather than applying the typical 5 percent payout rule to a market-indexed portfolio, the foundation directly pursues venture returns, effectively running its corpus like a family office while operating under foundation tax rules. This hybrid design means grantmaking capacity is directly tied to the venture book's performance — a feedback loop that imposes discipline on both sides of the house and makes Gideon Stein, in practice, the chief investment officer of a $72 million perpetual fund for social justice.

General information

Firm type

Endowment / Foundation

Year founded

1985

Location

Region

North America

Country

United States

City

New York

Corporate office

New York, NY, United States

Principals

Gideon Stein

President

Mary Ann Stein

Founding President and Chairwoman Emerita

Robert Efroymson

Co-founder

Clarence Efroymson

Co-founder

Dorothy Stein

Board Member and Secretary

Frequently asked questions

Who runs investment decisions at the Moriah Fund?

President Gideon Stein oversees both the grantmaking and the direct venture portfolio. The foundation operates without a separately named CIO or external investment committee, suggesting Stein is the central investment decision-maker alongside the board. The board includes Dorothy Stein as secretary and operates from the family's New York office.

How does the Moriah Fund generate the capital it grants out?

Unlike most foundations that outsource endowment management, Moriah directly invests its corpus in venture capital — the internal research record tags six distinct venture strategy classifications across what is roughly a $72 million asset base (Altss estimate). It also holds direct commercial real estate, including interests in Northern Manhattan through Argyle Holdings LLC.

Is the Moriah Fund a single-family office or a foundation?

It is legally a private foundation, but it operates with a hybrid architecture: the endowment is managed like a single-family office's venture portfolio rather than a traditional diversified foundation pool. Grantmaking priorities — informed by Mary Ann Stein's lifetime of advocacy — remain structurally separate from investment activities, though both report to the same president.

Where does the underlying wealth come from?

The capital originated with brothers Robert and Clarence Efroymson, whose family built wealth in Midwestern retail and real estate. The family's civic footprint extends to major arts institutions — they endowed the Efroymson Family Entrance Pavilion at the Indianapolis Museum of Art — and maintains a separate Efroymson Family Fund alongside the Moriah Fund.

Does the Moriah Fund participate in fund commitments or only direct deals?

The foundation's investment function is classified across multiple venture capital strategies, suggesting broad direct-deal activity rather than commitments to external fund managers. However, the foundation does not publicly disclose specific portfolio names or a formal policy excluding fund-of-funds allocations.

How is the Moriah Fund related to the Efroymson Family Fund?

Both are separate philanthropic entities tied to the Efroymson family. The Efroymson Family Fund operates as a distinct vehicle, and the founders — Robert and Clarence Efroymson — seeded the Moriah Fund in 1985 with Mary Ann Stein as its founding president. No public source describes a shared staff or shared investment committee between the two entities.

What is the Moriah Fund's known posture on co-investments alongside external GPs?

No public sourcing documents a co-investment practice. The foundation's lean staff — essentially Gideon Stein and the board — and its internal designation as a direct venture investor suggest it likely underwrites its own deals, but there is no verifiable statement on whether it syndicates alongside or independently of outside venture firms.

Profile maintained by using OSINT (open-source intelligence), regulatory filings, licensed data partners, and verified direct submissions. Read the methodology. Last updated: . Continuous refresh with full update cycles at least every 30 days.

Need institutional-grade insight on endowments & foundations?

Altss delivers:

Principals with verified direct contactsAllocation history by asset classOSINT-derived deal signals
Book a demo

Prefer a guided tour?

We’ll walk you through:

Interactive funding timelinesCustom mandate & allocation filters
Book a demo

More New York Endowment / Foundation profiles