California Billionaire Sergey Brin Opposes Proposed Wealth Tax

Billionaire Sergey Brin has emerged as a major player in California's electoral politics, thanks to his opposition to a proposed wealth tax that would target billionaires like himself.

After years of staying on the sidelines of electoral politics, Google cofounder Sergey Brin has become one of the most influential financiers in California, leveraging his vast fortune to shape state policy. His involvement began with Proposition 40, a ballot measure aimed at taxing billionaires' wealth.

Brin's organization, Building a Better California, has received over $102 million from him alone and is using this money to influence the outcome of various ballot measures beyond Prop 40. Other Silicon Valley billionaires, venture capitalists, and business leaders have also contributed hundreds of millions of dollars to the group.

The funds are being channeled into supporting ballot measures that counter the wealth tax, including Propositions 41 and 42. Building a Better California has spent more than $304 million so far on these efforts, with around $118.5 million dedicated specifically to opposing Prop 40.

Proposition 41 would introduce new rules for state spending, making it harder for funds raised by the billionaire tax to be used. Meanwhile, Proposition 42 aims to outlaw retroactive taxation, directly countering the wealth tax's provisions.

The strategy employed by Building a Better California gives opponents of the wealth tax multiple avenues to defeat it, even if Prop 40 receives more "yes votes than its counter-measures.

More than 70 current and former California billionaires have directed a record $612 million into state elections during the current cycle, according to an analysis by Politico. This massive influx of funds is primarily being channeled towards defeating Proposition 40, with nearly half of the money allocated for this purpose.

A significant portion of these billionaire donors have also contributed specifically to the fight against the wealth tax. At least 30 billionaires have put in over $293 million to oppose the proposed one-time tax on California's ultrawealthy individuals and trusts worth more than $1 billion as of January 1, 2026.

In addition to its efforts to defeat Proposition 40, Building a Better California has endorsed several other ballot measures. These include Propositions 1, 3, 37, 41, and 42, which are part of the organization's policy platform. Separate from this, Building a Better California has also invested $10 million in Proposition 45, a measure aimed at reforming California's environmental review process.

Proposition 40, the proposed wealth tax on billionaires, is set to appear on the November 3 ballot. If passed, it would impose a 5% tax on assets worth more than $1 billion held by individuals and certain trusts who were California residents as of January 1, 2026.

The Legislative Analyst's Office estimates that the state will likely collect tens of billions of dollars from this tax over several years, with 90% allocated towards healthcare and the remaining 10% directed towards education and food assistance.

The Service Employees International Union-United Healthcare Workers West has been at the forefront of advocating for California's healthcare system, particularly in light of federal funding cuts that threaten coverage for residents. This union-backed proposal seeks to generate additional revenue through a tax on billionaires, with 90% allocated towards healthcare and the remaining 10% directed towards education.

Billionaire Sergey Brin has been a vocal opponent of this proposal, citing concerns about its potential impact on California's economy and society. In an interview with The New York Times in April, he drew parallels between the proposed tax and the socialism he experienced during his childhood in the Soviet Union, expressing his desire to prevent California from adopting similar policies.

Rather than abandon the state's political landscape after his initial opposition, Brin took a more proactive approach by establishing Building a Better California. This organization received an initial $20 million contribution from Brin, which was followed by additional funding that brought his total contributions to $102 million by August, according to campaign finance filings.

Brin relocated to Nevada in December, ahead of the January 1 cutoff date that determines which billionaires would be subject to the proposed tax. Despite this move, he remains engaged in California's politics through Building a Better California and its efforts to prevent the measure from becoming law.

Wealthy tech executives have flocked to Building a Better California, the organization founded by billionaire Sergey Brin to fight Prop 40. Key figures like John Doerr of Kleiner Perkins and Patrick Collison of Stripe are now major contributors.

Mark Cuban, a self-proclaimed libertarian at heart who has been closely associated with Democrats in recent years, surprisingly found himself aligned with his fellow wealthy donors on this issue. He even got into a public spat with California politician Ro Khanna over the proposal, calling him insane.

Cuban's outburst was blunt: This is the biggest f* you in the history of entrepreneurship," he wrote on X. His comments reflect the strong emotions surrounding Prop 40.

Not all members of Building a Better California are on board with Brin's broad approach to politics, however. Former Google CEO Eric Schmidt had expressed frustration with the organization's anti-wealth-tax coalition after it failed to prevent California Democrats from endorsing Prop 40 in August.

A close confidant of former Google CEO Eric Schmidt revealed that Schmidt's frustration level was not extreme despite the endorsement of Prop 40 by California Democrats in August. This advisor clarified that Schmidt's involvement in politics is currently limited to his efforts to defeat the billionaires tax.

The distinction highlights a divergence between Schmidt and billionaire Sergey Brin, who had been working together on defeating Prop 40 but may have had differing priorities for their coalition's funds.