Key Takeaways
- • Sergey Brin has contributed $102 million to Building a Better California, a political organization that has become the central vehicle for Silicon Valley billionaires opposing Proposition 40, California's proposed one-time 5% wealth tax on billionaires, according to campaign finance filings.
- • Through Oct. 20, the group had spent more than $304 million, with approximately $118.5 million opposing Proposition 40 and $186 million supporting Propositions 41 and 42, per Capital & Main.
- • Propositions 41 and 42 would act as counters to the wealth tax; per the Legislative Analyst's Office, the tax could be blocked even if a majority of voters approve it if either measure receives more 'yes' votes than Proposition 40.
- • Politico's analysis found more than 70 current and former California billionaires directed a record $612 million into state elections in the 2026 cycle, with at least 30 billionaires contributing more than $293 million to the wealth tax fight.
- • Former Google CEO Eric Schmidt has reportedly diverged from Brin over the group's spending on broader measures such as Proposition 45, with a close Schmidt advisor saying his only political involvement is opposing the billionaires tax.
Summary
Google cofounder Sergey Brin, whose fortune Bloomberg estimates at $231 billion, has become one of California's most powerful political financiers through his opposition to Proposition 40, a one-time 5% tax on the assets of individuals and certain trusts worth more than $1 billion who were California residents on Jan. 1, 2026. The measure, which will appear on the Nov. 3 ballot, is designed to raise money to offset federal health care funding cuts, with 90% of proceeds going to health care and 10% to education and food assistance. The Legislative Analyst's Office estimates the state would probably collect tens of billions of dollars over several years. The measure was sponsored by the Service Employees International Union-United Healthcare Workers West and is backed by Sen. Bernie Sanders (I-Vt.) and Rep. Ro Khanna (D-Calif.).
Brin established Building a Better California in January with an initial $20 million contribution; by August his contributions had reached $102 million according to campaign finance filings. He relocated to Nevada in December, ahead of the Jan. 1 cutoff date. Other major contributors include Kleiner Perkins chairman John Doerr, former Google CEO Eric Schmidt, Stripe CEO Patrick Collison, and former Sequoia Capital partner Michael Moritz. Brin has also compared the proposal to the socialism he experienced growing up in the Soviet Union, in an April interview with the New York Times. Fortune reported that Brin did not immediately respond to a request for comment.
The organization's spending extends beyond the immediate fight against Proposition 40. Through Oct. 20, it had spent more than $304 million, with roughly $118.5 million opposing Proposition 40 and $186 million supporting Propositions 41 and 42, according to Capital & Main. Proposition 41 would bar the state from exempting new taxes from its spending limit and require audits of programs funded by new special taxes. Proposition 42 would outlaw retroactive taxation. The group has also endorsed Propositions 1, 3, 37, 41, and 42 and committed $10 million to Proposition 45, an environmental review measure, and $6 million to Proposition 37, a $25 billion homebuyer loan fund.
Politico's analysis found that more than 70 current and former California billionaires directed a record $612 million into state elections during the 2026 cycle, with nearly half going to groups working to defeat Proposition 40. Internal friction has emerged: the New York Post reported in August that Schmidt was frustrated with the coalition after California Democrats endorsed the measure, while a close Schmidt advisor told Fortune that Schmidt's only current political involvement is contributing to defeat of the billionaires tax, indicating divergence over spending on other measures such as Proposition 45. Mark Cuban has also publicly opposed the proposal, feuding with Rep. Khanna on X.
Brin established Building a Better California in January with an initial $20 million contribution; by August his contributions had reached $102 million according to campaign finance filings. He relocated to Nevada in December, ahead of the Jan. 1 cutoff date. Other major contributors include Kleiner Perkins chairman John Doerr, former Google CEO Eric Schmidt, Stripe CEO Patrick Collison, and former Sequoia Capital partner Michael Moritz. Brin has also compared the proposal to the socialism he experienced growing up in the Soviet Union, in an April interview with the New York Times. Fortune reported that Brin did not immediately respond to a request for comment.
The organization's spending extends beyond the immediate fight against Proposition 40. Through Oct. 20, it had spent more than $304 million, with roughly $118.5 million opposing Proposition 40 and $186 million supporting Propositions 41 and 42, according to Capital & Main. Proposition 41 would bar the state from exempting new taxes from its spending limit and require audits of programs funded by new special taxes. Proposition 42 would outlaw retroactive taxation. The group has also endorsed Propositions 1, 3, 37, 41, and 42 and committed $10 million to Proposition 45, an environmental review measure, and $6 million to Proposition 37, a $25 billion homebuyer loan fund.
Politico's analysis found that more than 70 current and former California billionaires directed a record $612 million into state elections during the 2026 cycle, with nearly half going to groups working to defeat Proposition 40. Internal friction has emerged: the New York Post reported in August that Schmidt was frustrated with the coalition after California Democrats endorsed the measure, while a close Schmidt advisor told Fortune that Schmidt's only current political involvement is contributing to defeat of the billionaires tax, indicating divergence over spending on other measures such as Proposition 45. Mark Cuban has also publicly opposed the proposal, feuding with Rep. Khanna on X.
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