Sergey Brin Leads $300 Million Effort to Block California Billionaire Tax

Google co-founder Sergey Brin has joined a group of wealthy tech executives to fund a massive campaign against California's proposed billionaire tax. The coalition, which includes DoorDash founder Tony Xu and Stripe co-founder Patrick Collison, has raised more than $300 million to defeat Proposition 40. This spending makes the contest the most expensive ballot measure fight in state history, according to David McCuan, a political science professor at Sonoma State University.

The measure would impose a one-time 5 percent tax on the assets of Californians who are billionaires. Supporters have raised only $32 million, creating a spending gap of nearly ten to one. The vote is scheduled for November 3. McCuan, who tracks state and local elections, noted that the financial disparity defines the current landscape of the race.

Mark Zuckerberg, founder of Meta, has not donated to the opposition. However, SEC filings reveal he informed the company's board that he intended to 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 prevent his relocation from affecting Meta's stock price. The board includes Xu and Collison, both of whom are actively funding the anti-tax campaign.

The volume of advertising has confused some voters. Brian Galle, a University of California at Berkeley economics professor who helped draft the proposal, received a flyer claiming the tax could apply to retirement savings. Galle stated that provision was not in his original text. Ashley Craig, a volunteer with the pro-tax group Patriotic Millionaires, said she frequently hears from constituents who believe the measure has secret provisions that would tax everyone.

Galle argued that the spending illustrates the inequality the tax aims to address. He stated, "The irony is that Prop 40 is meant to make democracy more equal, but the billionaires are using their money to avoid that." Francesco Trebbi, a professor at Berkeley's Haas School of Business, described the contest as "Sergey Brin v millions of Californians," suggesting it erodes trust in the system.

The fight has also split the Democratic party. The state party endorses the tax, but Craig said she has received little ground support from the organization. McCuan called the measure a proxy test between progressives and moderates. Governor Gavin Newsom, who is considering a 2028 presidential run, opposes the tax. He called it "poorly written" and warned that billionaires, whose collective wealth is estimated at 2.3 trillion dollars, might leave the state. Gubernatorial candidate Xavier Becerra and former congresswoman Katie Porter also oppose the measure.

Opponents are backing two other ballot measures. One bars new state taxes on personal property or retroactive taxes, while the other requires state auditors to review proposed tax measures for financial impact before a vote. If either measure receives more votes than the billionaire tax, it could negate the tax even if voters approve Proposition 40. A recent Public Policy Institute of California poll found voters narrowly support the tax but also back the two blocking measures. Mark Baldassare, the institute's survey director, noted that only about a third of citizen initiatives pass, placing the burden on the yes side.

Suzane Jiminez, chief of staff at the SEIU health workers union, which sponsored the measure, expressed confidence in the outcome. She said 3,000 volunteers are currently knocking on doors and distributing flyers. Senator Bernie Sanders and Congressman Ro Khanna have also rallied support across the state. McCuan suggested that even a defeat could benefit backers, who could blame moderates and target big tech as a political bogeyman.