A proposed one-time 5% wealth tax targeting California billionaires has gathered enough signatures to appear on the state’s November ballot, backers announced this weekend. The Service Employees International Union United Healthcare Workers West said it collected more than 1.5 million signatures — well above the 875,000 required to qualify the initiative — with the surplus intended to cover invalid or illegible names. The union, which represents more than 120,000 healthcare workers, is backing the measure to offset federal spending cuts it says threaten to close hospitals and strip millions of Californians of medical insurance.
The tax would apply a one-time 5% levy on the assets of roughly 200 California residents with a net worth of $1 billion or more, as of January 1 this year. Proponents estimate it would raise $100 billion in one-time revenue. The nonpartisan California Legislative Analyst’s Office projects tens of billions in upfront proceeds but has cautioned the measure could cost the state hundreds of millions annually if billionaires relocate as a result.
Opposition has been swift and well-funded. Sergey Brin contributed more than half of the $80 million raised in early 2026 by anti-tax group Building a Better California, with additional millions from former Google CEO Eric Schmidt and venture capitalist Michael Moritz. The California Business Roundtable received $3 million from Palantir cofounder Peter Thiel and $500,000 from Ripple Chairman Chris Larsen. Opponents are also paying signature-gatherers $15 per name to advance rival ballot measures, driving up the overall cost of the fight. Google cofounders Larry Page and Brin were among a handful of billionaires who relocated ahead of the proposed January 1 eligibility date.
Governor Gavin Newsom has opposed the tax, warning it could accelerate the departure of wealthy residents. None of California’s leading gubernatorial candidates have endorsed the measure, with San Jose Mayor Matt Mahan echoing Newsom’s concern that the levy poses a threat to innovation. Former Health Secretary Xavier Becerra has called the one-time structure an ineffective remedy even while criticizing current tax rates on the wealthy, and Representative Katie Porter has argued for taxing corporations rather than individuals.
Not all of Silicon Valley’s billionaires are lined up against it. Nvidia CEO Jensen Huang, whose net worth of $167 billion would make him liable for an $8 billion payment under the proposal, said at a Stanford Graduate School of Business panel earlier this month that California’s tax burden is worth it. Also on that panel was Representative Ro Khanna, who has co-sponsored federal legislation with Senator Bernie Sanders that would impose a 5% wealth tax on more than 1,000 billionaires nationally.
California would not be the first state to act. Washington state has adopted a 9.9% tax on millionaires taking effect in 2028, Maine has passed a 2% income tax surcharge on high earners, and New York City Mayor Zohran Mamdani is backing a pied-à-terre tax on homes valued at $5 million or more.
