The Rhombus Foundation
The Rhombus Foundation is a private foundation based in Wilmington, Delaware. It makes contributions to preselected charitable organizations and does not accept unsolicited requests for funds.
The Rhombus Foundation at a glance
In short: The Rhombus Foundation gave $334K across 28 grants in 2025 (avg $12K), top state New Jersey. Source: 2025 IRS Form 990-PF.
- Annual giving (2025)
- $333,500
- +3235.0% vs 2024
- Grants made (2025)
- 28
- +2700.0% vs 2024
- Average grant
- $11,911
- +19.1% vs 2024
- Median grant
- $10,000
- Total assets
- $649,477
- -33.7% vs 2024
- Primary geography
- New Jersey (39% of itemized 2025 grant dollars)
- Latest 990 filing
- Form 990-PF, 2025 View filing
Data from IRS Form 990-PF, 2025; updated October 2026.
How to apply to The Rhombus Foundation
- Accepts unsolicited proposals
- No
- How to Apply
-
The foundation contributes only to preselected charitable organizations and does not accept unsolicited requests for funds.
- Contact
Mailing address: Foundation Source 501 Silverside Rd, Wilmington, DE 19809-1377
Phone: (800) 839-1754
Application details from Grantable's research on the foundation's public materials; confirm on its website before applying.
Who The Rhombus Foundation funds
How this funder distributes its grants
Top Recipients
Top 10 recipients in 2025
The largest 2025 recipient was St Vincents Academy ($80K across 2 grants). Together the top 10 received $267K.
Grant Size Distribution
29 grants across all recorded years
The most common grant size was under $50K: 27 grants of 29 (93%).
Geographic Focus
Where this funder awards grants
Among 2025 grant dollars, 39% went to recipients in New Jersey, 15% to Georgia, 7% to the District of Columbia, and 3% to Virginia. The recipient state associated with a further 20% is unspecified.
Grant Distribution by State
Share of 2025 grant dollars across all 28 itemized grants.
States
Cities
How The Rhombus Foundation gives
- In 2025 it paid out 917% of its IRS minimum distribution (the 5% rule). Method
From the foundation's IRS Form 990-PF filings. Methodology.
Giving History
Giving Over Time
Total grant dollars and number of grants per year
From 2024 to 2025, annual grant giving ranged from $10K (2024) to $334K (2025). In 2025 it made 28 grants totaling $334K.
Grants by year
Grant recipients and amounts by year
| Recipient | Purpose | Amount |
|---|---|---|
| St Vincents Academy Newark, NJ | General & Unrestricted | $60,000 |
| Musical Dramatic Arts Foundation Inc Marietta, GA | General & Unrestricted | $50,000 |
| Africa Research Excellence Fund (Aref Africa) | General & Unrestricted | $40,000 |
| St Vincents Academy Newark, NJ | The Grace H. and Bernard A. Gay Scholarship fund | $20,000 |
| Ebunjan Performing Arts Association | General & Unrestricted | $15,000 |
| Try Association of Women Oyster Sellers | General & Unrestricted | $12,000 |
| Atlas Economic Research Foundation - Atlas Network Arlington, VA | IMANI Africa | $10,000 |
| Equal Justice Initiative Montgomery, AL | General & Unrestricted | $10,000 |
| Hope for Haiti Inc Naples, FL | General & Unrestricted | $10,000 |
| Human Rights Watch Inc New York, NY | General & Unrestricted | $10,000 |
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Financial History
Multi-year comparison from IRS filings
The foundation reported that during 2025 it distributed $333,590 from sources other than current income. Its filing states that this amount was at least 25% of its $980,261 in net assets at the beginning of the year and that the distributions resulted in a substantial contraction of assets. The foundation also stated that it had no plans for dissolution.
| Filing year | Total Assets | Revenue | Expenses | Grants paid | Grants | Qualifying Distributions | Net Investment Income | Distributable Amount |
|---|---|---|---|---|---|---|---|---|
| 2025 | $649,477 | $28,088 | $358,872 | $333,500 | 28 | $358,782 | $28,088 | $39,109 |
| 2024 | $980,261 | $999,511 | $19,250 | $10,000 | 1 | $19,250 | $11 | $1,869 |
Under IRS private-foundation payout rules, The Rhombus Foundation reported a distributable amount of $39K for 2025 — the minimum it must pay out in qualifying distributions.
Research compiled by Grantable AI from public sources. Last updated September 2026.
Grantmaking
In 2025, the foundation reported 28 grants totaling $333,500. Awards ranged from $1,000 to $60,000, with a median of $10,000. In 2024, it reported one grant totaling $10,000.
The largest reported 2025 grants included $60,000 and $20,000 to St. Vincents Academy, $50,000 to Musical Dramatic Arts Foundation Inc., and $40,000 to Africa Research Excellence Fund (AREF Africa). Other grants included $15,000 to Ebunjan Performing Arts Association and $12,000 to Try Association of Women Oyster Sellers. The foundation also reported $10,000 grants to Atlas Economic Research Foundation – Atlas Network, Equal Justice Initiative, Hope for Haiti Inc., Human Rights Watch Inc., International Crisis Group, and Médecins Sans Frontières USA Inc.
Leadership & Key People
Leadership team and compensation from IRS filings
Omotunde AJ Mahoney was listed as the foundation’s responsible party, president, and director on its 2025 filing.
The Rhombus Foundation is led by Omotunde AJ Mahoney, Responsible Party, President & Director since 2025 (on filings since 2024) — the only officer listed, and uncompensated.
Officers on the 2025 filing
Omotunde AJ Mahoney
Responsible Party, President & Director
President, Director, Secretary & Treasurer → Responsible Party, President & Director, 2025
On filings since 2024
1 hr/week
No compensation reported
Data from IRS Form 990 filings, 2024–2025. "On filings since" is the earliest filing we hold that lists the person; hours are average hours per week as reported.
Frequently asked questions about The Rhombus Foundation
How much does The Rhombus Foundation give each year?
The Rhombus Foundation gave $334K across 28 grants in 2025, according to its 2025 IRS Form 990-PF. In 2024 it gave $10K across 1 grant.
What is The Rhombus Foundation's typical grant size?
The Rhombus Foundation's median grant in 2025 was $10,000, and its average grant was $11,911, across 28 grants on its 2025 IRS Form 990-PF.
Where does The Rhombus Foundation give grants?
The Rhombus Foundation's top state is New Jersey, with 39% of the grant dollars itemized on its 2025 IRS Form 990-PF. The next largest states were Georgia (15%) and District of Columbia (7%). The most frequent recipient cities were Montclair, NJ (8 grants), Newark, NJ (3 grants) and Washington, DC (3 grants).
Does The Rhombus Foundation give general operating support?
Yes: 71% of The Rhombus Foundation's 2025 grants with a stated purpose (20 of 28) were for general or operating support, per its 2025 IRS Form 990-PF.
Who are The Rhombus Foundation's largest grantees?
The Rhombus Foundation's largest 2025 grantees include St Vincents Academy ($80,000 across 2 grants), Musical Dramatic Arts Foundation Inc ($50,000) and Africa Research Excellence Fund (Aref Africa) ($40,000), according to its 2025 IRS Form 990-PF. Together they received 51% of its itemized 2025 grant dollars.
How large is The Rhombus Foundation?
The Rhombus Foundation reported $649K in total assets on its 2025 IRS Form 990-PF. It paid out $359K in qualifying distributions that year, against a required minimum of $39K (roughly 5% of its investment assets).
How do I apply for a grant from The Rhombus Foundation?
The foundation contributes only to preselected charitable organizations and does not accept unsolicited requests for funds. Eligibility and process details are in the grantmaking section of this profile. See how to apply ↑
What is The Rhombus Foundation's EIN?
The Rhombus Foundation's EIN (Employer Identification Number) is 99-4031209. IRS Form 990 filing data is available on this page for 2024–2025.
Does The Rhombus Foundation accept unsolicited proposals?
No, according to Grantable's research on the foundation's published guidelines. See how to apply ↑
Data last updated October 2026. Sourced from IRS Form 990-PF filings. Research dossier generated September 2026.
Data update history
(3)
When this profile's IRS filing data changed on Grantable
- Updated Form 990-PF for fiscal year 2024 (received by the IRS May 9, 2025)
- Added Form 990-PF for fiscal year 2025 (received by the IRS June 12, 2026)
- IRS filings on file for fiscal year 2024
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Figures come from The Rhombus Foundation's IRS filings (methodology). AI-written summaries, news items and logos are not covered by the open licence. Spot an error? Email hello@grantable.co.
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