Editor’s Note: This article was originally published on January 15, 2026.
If public estimates are to be believed, Sergey Brin is worth tens of billions of dollars more than Bill Gates, Warren Buffett or Michael Bloomberg, let alone George Soros. Yet his grantmaking has been nowhere near their level — until now.
According to newly released IRS filings, the Sergey Brin Family Foundation nearly doubled its grantmaking in 2024, sending out awards totalling $699 million, up 86% from the year before. His newer 501c4 operation, Catalyst4, sent out another $44 million in grants. And the ramp-up apparently continued in a big way last year. Brin’s foundation granted $1.1 billion in 2025, according to a spokesperson.
At that level of grantmaking, the Google cofounder ranks among the largest living donors in the world. He’s well exceeded the legacy institutions of yesteryear’s barons: His total for 2024 rivals what the Rockefeller and MacArthur foundations granted that year combined, and his 2025 total well exceeds that figure, though he’s still a long way from the levels of today’s biggest titans, like Bloomberg ($3.7 billion in 2024) or Gates ($8 billion).
What Brin shares with those centibillionaires is that his wealth is still growing a lot faster than his giving, even at this new level — i.e., there’s potential for a whole lot more. Estimates put his fortune between $140 billion (Forbes) and $250 billion (Bloomberg), while his philanthropic donations over the past 20 years total approximately $5 billion, according to a representative.
In 2025, Brin made two major stock donations, according to reporting by Bloomberg News. In May, he gifted $700 million in shares of Alphabet, Inc., Google’s parent company, to Catalyst4, which already had $1.1 billion in assets. In November, he donated another $1.1 billion, nearly all of it to Catalyst4. In all, the 501c4 received about $1.5 billion, while his foundation got around $190 million, according to statements from his representatives to Bloomberg.
Brin’s philanthropy should be of interest not only to organizations working in his top causes, climate change and Parkinson’s research, but to anyone curious about the future of the sector. The tech billionaire’s evolving giving over the past few years is one of the highest-profile examples of an approach favored by many of today’s ultra-rich donors: massive financial resources combined with limited transparency and a flexible, lean format.
Stock gains have rapidly grown his foundation’s endowment into a peer of top legacy funders, yet it still lacks a website and has a minimal public presence. The foundation’s grantmaking, which as recently as 2018 stood at $55 million, exceeded that of all but the nation’s dozen or so largest philanthropic institutions in 2024. And with $2.6 billion and counting transferred to a 501c4, Brin is the latest reminder that today’s megadonors are comfortable using many vehicles to pursue the change they seek.
Above all, the eye-popping and fast-rising net wealth estimates for Brin and his fellow centibillionaires — not to mention the rest of the billionaire class — remind us that the biggest impacts may be yet to come.
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Where did Brin’s foundation send checks in 2024?
No big surprise at the organization at the top of Brin’s award list: The foundation’s close partner and favorite grantee, the Michael J. Fox Foundation for Parkinson’s Research, once again accounted for an outsized share of its grantmaking, receiving 17 awards totaling nearly $253 million in 2024, or about a third of all grant dollars.
Major awards also went to other health research projects, with checks going to UCSF ($68 million, five grants), Stanford University ($32 million, five grants), BD2 LLC ($20 million) and Broad Institute ($17.5 million).
In all, $281 million went to Parkinson’s research and nearly $98 million to research on bipolar disorder, autism and other conditions of the central nervous system, according to a spokesperson.
Climate grantees — an area of major growth for Brin’s giving recently — got another $232 million, according to updated figures from the foundation. Two long-favored major intermediaries were the largest beneficiaries, the Climate Imperative Foundation ($49 million) and United States Energy Foundation ($32.5 million, four awards).
The ClimateWorks network of regrantors also received several awards, with awards going to ClimateWorks Foundation ($14 million, three grants), Asia-focused Tara Climate ($10 million, two grants) and European Climate Foundation ($6 million).
Other major climate and environmental awards went to electrification nonprofit Rewiring America ($12 million), scientific research convener Aspen Global Change Institute ($10 million) and offshore wind organization Ocean Energy Pathway ($6 million). There was also a $19.8 million gift to Stanford University for its WastewaterSCAN program on wastewater science and virus monitoring.
Who got Brin’s 501c4 support in 2024?
Catalyst4’s funding fell by nearly half in 2024, to $44 million from $84 million the year before. But that’s no shock for an operation that’s just a few years old, and is still legally headquartered in a UPS store. (Which, in case you hadn’t heard, is a favored home for Silicon Valley’s low-profile, multibillion-dollar funds.)
Catalyst4 issued just nine grants in 2024, with the largest going to the progressive regrantor Sixteen Thirty Fund ($25 million), clean energy advocacy group Energy Action Fund ($6.6 million), environmental stalwart League of Conservation Voters ($3.5 million) and a community foundation, the Humboldt Area Foundation ($2.6 million). Several are past grantees. One of the few grants for medical research was to the neuroscience nonprofit Spark NS ($3.2 million).
As that list shows, nearly all of Catalyst4’s grantmaking backed climate action ($41 million), while just a small share supported central nervous system diseases and disorders such as Parkinson’s ($3 million), according to its 990. However, the fund spent another $33 million on program service expenses for the latter cause, largely as part of what it called “collaborative arrangements to fund research and development,” while corresponding expenses for climate were under $1 million.
Nearly $25 million, or about 60%, of Catalyst4 grants in 2024 went overseas, with just over half landing in Europe ($14 million) and the rest in the Middle East and Africa ($11 million).
Michael Kavate covers climate philanthropy and billionaire donors. He welcomes feedback, disagreements, tips and requests.
