Sergey Brin funds political group to oppose California wealth tax and expand influence

Google co-founder Sergey Brin has become a leading financier of California’s anti-wealth-tax campaign, contributing $102 million to the political organization Building a Better California. The group, which Brin founded in January with an initial $20 million, has spent more than $304 million through Oct. 20 on ballot initiatives, including $118.5 million to oppose Proposition 40 and $186 million to back Propositions 41 and 42, which aim to limit the state’s ability to levy new taxes.

Building a Better California also supports other measures, such as Propositions 1, 3, 37, 41, 42 and has allocated $10 million to Proposition 45, which addresses environmental review processes, and $6 million to Proposition 37, a proposal for a $25 billion homebuyer loan fund.

Proposition 40, slated for the Nov. 3 ballot, would impose a one-time 5 percent tax on the assets of California residents with wealth over $1 billion, directing most of the revenue to healthcare and a portion to education and food assistance. The measure is backed by the Service Employees International Union-United Healthcare Workers West and progressive politicians including Sen. Bernie Sanders and Rep. Ro Khanna.

Brin, whose fortune is estimated at $231 billion, has warned that the tax resembles the socialism he experienced in the former Soviet Union. He relocated to Nevada before the Jan. 1 residency cutoff that would make him subject to the tax.

Other prominent donors to Building a Better California include Kleiner Perkins chairman John Doerr, former Google CEO Eric Schmidt, Stripe CEO Patrick Collison and former Sequoia Capital partner Michael Moritz. Mark Cuban, a billionaire who has supported Democratic candidates, has also criticized the tax proposal.

"Schmidt’s only current involvement in politics is his contributions to defeating the billionaires tax," a close advisor told Fortune.

Analyses by Politico and Capital & Main indicate that more than 70 California billionaires have directed a record $612 million into state elections during the 2026 cycle, with nearly half aimed at defeating Proposition 40. The coordinated spending reflects a broader effort by wealthy tech executives to shape California’s fiscal policy beyond the immediate wealth-tax battle.