Method & sources

Sources

• IRS Form 990-PF XML corpus, year 2025. 16 monthly IRS TEOS batches, 130,346 foundation filings parsed. Every grant line links to the funder's ProPublica Nonprofit Explorer page (a human-checkable list of that funder's filings) and states its filing reference: the IRS TEOS batch it comes from plus the OBJECT_ID. The IRS publishes filings inside monthly batch archives and does not serve individual filing XML at its own address, so batch + OBJECT_ID is stated as a reference, not a link.
• UK charity register (Charity Commission public extract, 3,141 grantee names submitted). Grant rows flagged ✓ carry the matched UK charity number.
• 360Giving (via api.threesixtygiving.org) for the UK funder side: 2,217 UK recipients, of which 89 are Welsh and 114 are funded by two or more of the peer funders.

Three coverage limits — read these before relying on anything above

1. Only 62.9% of 990-PF filings itemise grantees. 82,037 of 130,346 filings list individual grants; the rest report totals only, so their UK giving is invisible here. The grant list is a large sample of US→UK giving, not a census.
2. 56.3% of grantee names resolve to a UK charity number. Name matching is exact-plus-fuzzy against the Charity Commission register; unregistered organisations (churches, schools, community groups) stay unmatched. A "✓" is verified; an unresolved name is a lead, not a certainty.
3. Donor-advised funds are opaque. DAF sponsors (Fidelity Charitable, Schwab, Vanguard Charitable and similar) file a single 990-PF listing thousands of grants; the ultimate donor cannot be seen. Several of the largest rows in this data are DAF-mediated, and we say so rather than guess.

UK-only funding items come from 360Giving, which covers UK grantmakers who publish voluntarily — coverage is good for large foundations, thin for small local ones.