Arizona · Nonprofit
BOYCE THOMPSON SOUTHWESTERN ARBORETUM
BOYCE THOMPSON SOUTHWESTERN ARBORETUM (Arizona) receives grants from 20 organizations whose IRS filings report $1,040,967 to it, the largest being MARGARET T BIDDLE TRUST TWELFTH ($256,111). 7 of them have funded it in more than one year.
- Revenue FY2025
- $5.1M
- Funders on record
- 20
- Grants received
- $1.0M
- Net assets
- $10M
What Boyce Thompson Southwestern Arboretum does
Program
The Boyce Thompson Southwestern Arboretum (btsa) is arizona's oldest and largest botanical institution. Btsa was founded in 1924 by william boyce thompson, a mining magnate who understood the importance of plants as the ultimate source of our survival and well-being. That legacy continues today as btsa offers tours, classes and events, bringing a wide community together in appreciation of the astounding diversity of its growing collection. Located an hour east of arizona's state capital, btsa holds collections of desert plants from the united states, mexico, australia, madagascar, india, china, japan, israel, south america, the middle east, africa, the mediterranean, and the arabian peninsulaall told 4,025 taxa and 20,000 plants within 135 acres of gardens. Situated on 372 acres of scenic upland sonoran desert with nearly five miles of trails, btsa is arizona's oldest and largest botanical garden and one of arizona's top tourism sites.
$4,806,483 spent
The program described on its FY2024 Form 990-PF.
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.
Balance sheet
Total assets and total liabilities at each year end, in dollars. The largest one-year move in total assets was 2020 to 2021, from $9.8M to $11M (+14%).
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
Kim Gray
Executive director
Board chair
Jared Langkilde
Chair
As listed on its FY2025 Form 990-PF.
Who funds it, year by year
2018 → 2023: the base broadened from 1 funder to 7 funders, grant income rose $7k → $128k.
5 of 20 of your funders are donor-advised or pass-through sponsors (tagged DAF) — 42% 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 BOYCE THOMPSON SOUTHWESTERN ARBORETUM’s funders (the co-funder graph). 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
BOYCE THOMPSON SOUTHWESTERN ARBORETUM has a broad base — no single funder exceeds 25% of grant income, and it takes 3 funders to reach half.
the vertical line marks half of all grant income — 3 funders to its left
42% 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 BOYCE THOMPSON SOUTHWESTERN ARBORETUM.
Largest funder’s share by year: 2018 100% · 2019 100% · 2020 93% · 2021 71% · 2022 51% · 2023 39% — 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
17% of BOYCE THOMPSON SOUTHWESTERN ARBORETUM's funders are still giving 3 years after their first grant; 35% 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
BOYCE THOMPSON SOUTHWESTERN ARBORETUM draws 53% of its grant income from funders outside Arizona, across 7 states in all.
In-state vs out-of-state, by year
Funder states come from each funder’s own filing. $432k arriving through sponsors registered in 5 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.
Organizations like BOYCE THOMPSON SOUTHWESTERN ARBORETUM
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 Arizona
Nationally
Read directly from this organization’s own Form 990, as neutral context.
Screen this organization
A dated, signed PDF of the compliance screen for BOYCE THOMPSON SOUTHWESTERN ARBORETUM: 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 BOYCE THOMPSON SOUTHWESTERN ARBORETUM?
- BOYCE THOMPSON SOUTHWESTERN ARBORETUM (Arizona) receives grants from 20 organizations whose IRS filings report $1,040,967 to it, the largest being MARGARET T BIDDLE TRUST TWELFTH ($256,111). 7 of them have funded it in more than one year.
- How many funders does BOYCE THOMPSON SOUTHWESTERN ARBORETUM have?
- IRS filings report 20 organizations giving $1,040,967 in grants to BOYCE THOMPSON SOUTHWESTERN ARBORETUM, 7 of which have funded it in more than one year.
- Who is the largest funder of BOYCE THOMPSON SOUTHWESTERN ARBORETUM?
- MARGARET T BIDDLE TRUST TWELFTH is the largest funder on record, with $256,111 in grants. The full list of funders is on this page.
- How can an organization like BOYCE THOMPSON SOUTHWESTERN ARBORETUM find more funders?
- Start with the funders already giving here, then look at the foundations that back similar organizations in Arizona. 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 20 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