California · Nonprofit
OPEN MEDICINE FOUNDATION
OPEN MEDICINE FOUNDATION (California) receives grants from 84 organizations whose IRS filings report $12,593,210 to it, the largest being STUPSKI FOUNDATION ($2,000,000). 40 of them have funded it in more than one year.
- Revenue FY2025
- $5.5M
- Funders on record
- 84
- Grants received
- $13M
- Net assets
- $4.4M
What Open Medicine Foundation does
Mission
Funds collaborative medical research and education for multi-system chronic complex diseases.
As stated on its FY2025 Form 990.
Program
The organization supports research through 6 collaborative research centers and by bringing together a community of "thought leaders," patients, clinicians and researchers for targeted initiatives. Open Medicine Foundation is currently focused on researching myalgic encephalomyelitis/chronic fatigue syndrome ("me/cfs"), and long covid, in hopes of also revealing answers to other multi system chronic complex diseases that share similar symptoms. Its 4 primary goals are to: 1).frame clear disease mechanisms and models. 2).find effective treatment and diagnostic markers. 3). Increase accurrate diagnoses. 4). Ensure access to quality care.
$3,774,197 spentof which $2,525,383 as grants100% of program spending
The program described on its FY2025 Form 990. Program spending in total: $3,774,197.
The organization over time
Each line starts at 100 in 2017, so what you read is the shape rather than the size: 150 means half as much again as 2017, 50 means half. The number beside each label in the key is where it ended. The shaded band is where the middle 50% of its peers' revenue would sit, given their growth.
Balance sheet
Total assets and total liabilities at each year end, in dollars. The largest one-year move in total assets was 2017 to 2018, from $3.1M to $8.0M (+156%).
How it's funded, over time
Each bar is one year's revenue split into where it came from, and every bar is the same height — these are shares, not amounts, so a year that raised twice as much looks the same size. Hover a bar for the split.
Government-grant reliance: 2021 3% · 2023 3%. Grants only. Government contracts and fees sit inside program revenue.
94% of OPEN MEDICINE FOUNDATION’s revenue is contributions — more reliant on donations than three-quarters of its peers (51% for the typical peer).
Surplus & reserves
Operating surplus or deficit each year, and months of liquidity in hand. 4 of the last 9 reported years ran a deficit.
reserve
Leadership and staff
The officers, directors, trustees and key employees listed on each return. Joined and no longer listed compare each filing with the year before, matching people by surname and first initial; a year after a gap, or a roster under three people, has no comparison.
Chief executive
Linda Tannenbaum
CEO/president
As listed on its FY2025 Form 990.
Who funds it, year by year
2017 → 2023: the base broadened from 9 funders to 29 funders, grant income rose $868k → $983k.
27 of 84 of your funders are donor-advised or pass-through sponsors (tagged DAF) — 48% of grant dollars received. That money is really individual donors directing a sponsor; the institutions to cultivate are the non-DAF funders.
Left out of every figure on this page: $172k from one payer (the same organization on both sides, largest Open Medicine Foundation). These are real filings, and they are not money OPEN MEDICINE FOUNDATION raised.
From the IRS filings of OPEN MEDICINE FOUNDATION’s funders (the co-funder graph). Top 30 of 84 funders by total. Association, not causation. Trends are read to FY2023, the last fiscal year that has finished arriving. FY2024–FY2026 are still being filed and are shown unshaded; they do not move any figure on this page.
How concentrated its funding is
OPEN MEDICINE FOUNDATION has a broad base — no single funder exceeds 16% of grant income, and it takes 6 funders to reach half.
the vertical line marks half of all grant income — 6 funders to its left
48% of the income these shares are computed over arrives through pass-through sponsors or from payers whose filings do not say what kind of payment it is. Concentration is still measured over all of it, because the money is real; what it does not support is a claim about how many institutions have chosen to fund OPEN MEDICINE FOUNDATION.
Largest funder’s share by year: 2017 46% · 2018 84% · 2019 39% · 2020 32% · 2021 39% · 2022 18% · 2023 17% — diversifying over time.
“Effective funders” = inverse Herfindahl index (1 / Σ shareᵢ²) — the number of equal-sized funders that would give the same concentration. Trends are read to FY2023, the last fiscal year that has finished arriving. FY2024–FY2026 are still being filed and are shown unshaded; they do not move any figure on this page.
How long its funders stay
33% of OPEN MEDICINE FOUNDATION's funders are still giving 3 years after their first grant; 48% give in more than one year at all.
Share of funders still giving k years after their first recorded grant, pooled across every acquisition cohort. A funder counts as retained in a year only if it made a grant that year. Measured to FY2023, the last fiscal year that has finished arriving — a funder cannot be counted as lapsed in a year most filers have not reached.
Where its funders are
OPEN MEDICINE FOUNDATION draws 54% of its grant income from funders outside California, across 24 states in all.
In-state vs out-of-state, by year
Funder states come from each funder’s own filing. $6.0M arriving through sponsors registered in 16 states is excluded from the map and the split above: a sponsor holds money on a donor’s behalf, so its registered address would place those dollars somewhere no donor need ever have been. Trends are read to FY2023, the last fiscal year that has finished arriving. FY2024–FY2026 are still being filed and are shown unshaded; they do not move any figure on this page.
Against its field
OPEN MEDICINE FOUNDATION holds deeper cash reserves than three-quarters of the 5,002 health nonprofits its size.
this organization peer median middle 50% of peers· 5,002 health nonprofits $1M–$10M, FY2025
Organizations like OPEN MEDICINE FOUNDATION
Organizations whose mission and program text most resemble this one, by semantic similarity over every organization in the US filings — the closest peers, and often the clearest route to shared or prospective funders.
In California
Nationally
Read directly from this organization’s own Form 990, as neutral context.
Where the money goes
83% of spending goes to programs.
Governance
Public support
92%
Share of support from the public (Schedule A) — the basis for its public-charity status.
Footprint & structure
Files a return copy in 28 states
Screen this organization
A dated, signed PDF of the compliance screen for OPEN MEDICINE FOUNDATION: IRS status (Business Master File, Publication 78, auto-revocation), the OFAC sanctions lists, the Internal Revenue Bulletin, and California registration, with the Rev. Proc. 2018-32 §8.01 reliance elements stated element by element. Generated from the current files at the moment you download it.
Screens are triage, not determinations; a source that cannot be read reports not screened, never clear. Screen this nonprofit · How the screen works · on the API as GET /api/screening/{ein}?format=pdf
Questions and answers
- Who funds OPEN MEDICINE FOUNDATION?
- OPEN MEDICINE FOUNDATION (California) receives grants from 84 organizations whose IRS filings report $12,593,210 to it, the largest being STUPSKI FOUNDATION ($2,000,000). 40 of them have funded it in more than one year.
- How many funders does OPEN MEDICINE FOUNDATION have?
- IRS filings report 84 organizations giving $12,593,210 in grants to OPEN MEDICINE FOUNDATION, 40 of which have funded it in more than one year.
- Who is the largest funder of OPEN MEDICINE FOUNDATION?
- STUPSKI FOUNDATION is the largest funder on record, with $2,000,000 in grants. The full list of funders is on this page.
- How can an organization like OPEN MEDICINE FOUNDATION find more funders?
- Start with the funders already giving here, then look at the foundations that back similar organizations in California. The funding by cause and by state pages list the largest funders for a given area and how to approach them.
These figures are read directly from IRS Form 990 / 990-PF e-file XML: this organization’s own return for FY2025 (financials across 2017–2025), and the filings of 84 funders that report grants to it. “On record” means captured in the filings we have parsed — a funder that does not e-file, or whose grant detail is not itemized, will not appear. Filings run roughly 12–24 months behind. Trends on this page end at FY2023, the last fiscal year that has finished arriving; later years are shown and marked, and move no figure. Data on this page was exported October 22, 2026. What this page cannot tell you · view filing