California · Nonprofit
FOUNDATION FOR SAN MATEO COUNTY LIBRARIES
FOUNDATION FOR SAN MATEO COUNTY LIBRARIES (California) receives grants from 17 organizations whose IRS filings report $1,308,443 to it, the largest being GS DONOR ADVISED PHILANTHROPY FUND FOR WEALTH MANAGEMENT INC ($500,000). 8 of them have funded it in more than one year, and 83% of the money arrives through donor-advised or pass-through sponsors rather than from an institution directly.
- Revenue FY2025
- $799k
- Funders on record
- 17
- Grants received
- $1.3M
- Net assets
- $1.3M
What Foundation for San Mateo County Libraries does
Mission
Provide annual resources to support the san mateo county libraries' goals and initiatives.
As stated on its FY2025 Form 990.
Programs
Library support: the foundation is creating an annual support program that supports systemwide initiatives of the san mateo county libraries. San mateo county libraries serves the diverse communities of atherton, belmont, brisbane, east palo alto, foster city, half moon bay, millbrae, pacifica, portola valley, san carlos, woodside, and the unincorporated areas of san mateo county the foundation will fund innovative programs and services of the library system.
$71,415 spent100% of program spendingFeasibility study: began exploring the feasibility of launching a capital campaign in support of a new library in east palo alto.
The 2 programs described on its FY2024 Form 990, listed largest first by expense. Program spending in total: $71,415.
The organization over time
Each line starts at 100 in 2019, so what you read is the shape rather than the size: 150 means half as much again as 2019, 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 2024 to 2025, from $605k to $1.3M (+116%).
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: 2022 4% · 2024 25% · 2025 9%. Grants only. Government contracts and fees sit inside program revenue.
99% of FOUNDATION FOR SAN MATEO COUNTY LIBRARIES’s revenue is contributions — more reliant on donations than three-quarters of its peers (62% for the typical peer).
Surplus & reserves
Operating surplus or deficit each year, and months of liquidity in hand. 1 of the last 7 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.
Board chair
Caiti Busch
Chair
As listed on its FY2025 Form 990.
Who funds it, year by year
2019 → 2023: the base broadened from 2 funders to 7 funders, grant income rose $50k → $56k.
7 of 17 of your funders are donor-advised or pass-through sponsors (tagged DAF) — 83% of grant dollars received. That money is really individual donors directing a sponsor; the institutions to cultivate are the non-DAF funders.
From the IRS filings of FOUNDATION FOR SAN MATEO COUNTY LIBRARIES’s funders (the co-funder graph). Top 16 of 17 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
FOUNDATION FOR SAN MATEO COUNTY LIBRARIES leans on a few funders — its largest provides 38% of grant income and the top three 77%; half comes from just 2 funders.
the vertical line marks half of all grant income — 2 funders to its left
89% 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 FOUNDATION FOR SAN MATEO COUNTY LIBRARIES.
Largest funder’s share by year: 2019 99% · 2020 56% · 2021 38% · 2022 77% · 2023 54% — 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 FOUNDATION FOR SAN MATEO COUNTY LIBRARIES's funders are still giving 3 years after their first grant; 47% 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
83% of FOUNDATION FOR SAN MATEO COUNTY LIBRARIES's grant income arrives through donor-advised or pass-through sponsors, whose addresses record where the money is held rather than where the donor is. Of the $224k that is directly attributable, 100% of it comes from California funders.
In-state vs out-of-state, by year
Funder states come from each funder’s own filing. $1.1M arriving through sponsors registered in 6 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
FOUNDATION FOR SAN MATEO COUNTY LIBRARIES runs a healthier operating margin than three-quarters of the 7,175 community improvement nonprofits its size.
this organization peer median middle 50% of peers· 7,175 community improvement nonprofits $100k–$1M, FY2025
Read directly from this organization’s own Form 990, as neutral context.
Where the money goes
73% of spending goes to programs.
Governance
Public support
99%
Share of support from the public (Schedule A) — the basis for its public-charity status.
Footprint & structure
Files a return copy in 1 state
Screen this organization
A dated, signed PDF of the compliance screen for FOUNDATION FOR SAN MATEO COUNTY LIBRARIES: 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 FOUNDATION FOR SAN MATEO COUNTY LIBRARIES?
- FOUNDATION FOR SAN MATEO COUNTY LIBRARIES (California) receives grants from 17 organizations whose IRS filings report $1,308,443 to it, the largest being GS DONOR ADVISED PHILANTHROPY FUND FOR WEALTH MANAGEMENT INC ($500,000). 8 of them have funded it in more than one year, and 83% of the money arrives through donor-advised or pass-through sponsors rather than from an institution directly.
- How many funders does FOUNDATION FOR SAN MATEO COUNTY LIBRARIES have?
- IRS filings report 17 organizations giving $1,308,443 in grants to FOUNDATION FOR SAN MATEO COUNTY LIBRARIES, 8 of which have funded it in more than one year.
- Who is the largest funder of FOUNDATION FOR SAN MATEO COUNTY LIBRARIES?
- GS DONOR ADVISED PHILANTHROPY FUND FOR WEALTH MANAGEMENT INC is the largest funder on record, with $500,000 in grants. The full list of funders is on this page.
- How can an organization like FOUNDATION FOR SAN MATEO COUNTY LIBRARIES 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.
Play a game about who funds Foundation for San Mateo County Libraries →
These figures are read directly from IRS Form 990 / 990-PF e-file XML: this organization’s own return for FY2025 (financials across 2019–2025), and the filings of 17 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 14, 2026. What this page cannot tell you · view filing