California Billionaire Tax Faces Record $300 Million Opposition Push

California voters will decide on November 3 whether to approve a one-time 5 percent tax on the assets of the state's billionaires. The campaign against the measure, known as Prop 40, has become the most expensive ballot fight in the state's history. David McCuan, a political science professor at Sonoma State University who tracks local elections, identified the record spending levels.

Opponents have raised more than $300 million to block the tax. This sum far exceeds the $32 million collected by supporters. Major donors to the opposition include Google co-founder Sergey Brin, DoorDash founder Tony Xu, Stripe co-founder Patrick Collison, Ripple co-executive chairman Chris Larsen, and venture capitalists John Doerr, Michael Moritz, and Vinod Khosla.

Meta founder Mark Zuckerberg has not donated directly to the opposition. However, Meta SEC filings show that he informed the company's board, which includes Xu and Collison, that he would purchase a home outside the state to avoid the tax. The board subsequently created a new class of shares for Zuckerberg to use for payment, a move designed to protect Meta's stock price from the potential impact of his relocation.

The volume of advertising and mailers has generated confusion among the electorate. Brian Galle, a University of California at Berkeley economics professor who helped draft the proposal, stated that some flyers falsely claimed the tax could apply to retirement savings. Ashley Craig, a volunteer with the pro-tax group Patriotic Millionaires, reported hearing from voters that the measure contains secret provisions affecting all residents. Both noted that any future changes to the tax would require a two-thirds majority in the state assembly.

The spending disparity has drawn criticism from academics. Galle called the situation ironic, noting that billionaires are using their wealth to counter a measure intended to make democracy more equal. Francesco Trebbi, a professor at Berkeley's Haas School of Business, described the contest as "Sergey Brin v millions of Californians," arguing that it erodes public trust in the system.

The issue has also created a divide within the Democratic Party. While the state party endorsed the tax, Craig said she has received limited ground support from the organization. McCuan characterized the vote as a proxy battle between progressives and moderates. Governor Gavin Newsom, who opposes the measure, called it "poorly written" and warned that billionaires, whose combined wealth is estimated at 2.3 trillion dollars, might leave the state if the tax passes. Gubernatorial candidate Xavier Becerra and former congresswoman Katie Porter also oppose the proposal.

Opponents have backed two additional ballot measures. One would bar new state taxes on personal property or retroactive taxes, while the other requires state auditors to review financial impacts before a vote. If either measure passes with more votes than Prop 40, it could negate the billionaire tax. A recent Public Policy Institute of California poll found that voters narrowly support the tax but also back the two opposing measures. Mark Baldassare, the institute's survey director, noted that only about one-third of citizen initiatives pass, placing the burden of proof on the yes side. Suzane Jiminez, chief of staff at the SEIU health workers union, reported that 3,000 volunteers are currently canvassing and that Senator Bernie Sanders and Congressman Ro Khanna have rallied support.