Brin Leads $300 Million Push Against California Billionaire Tax

The race to decide a new California tax has become the most expensive ballot measure fight in state history. Voters will cast ballots on November 3 on Proposition 40, a one-time 5 percent tax on the assets of billionaires residing in the state. The opposition has raised more than $300 million to defeat the measure, while supporters have collected only $32 million.

The funding surge follows a rapid timeline of political maneuvering. David McCuan, a political science professor at Sonoma State University, tracks these elections and confirmed the record-breaking spend. Key donors include Google co-founder Sergey Brin, DoorDash founder Tony Xu, Stripe co-founder Patrick Collison, and Ripple co-executive chairman Chris Larsen. Venture capitalists John Doerr, Michael Moritz, and Vinod Khosla also contributed to the anti-tax effort.

Mark Zuckerberg did not donate directly to the opposition, but his actions influenced the campaign's urgency. Meta’s SEC filings revealed that Zuckerberg told the board he would purchase a home outside California to avoid the levy. The board subsequently created a new class of shares for him to use for payment, a move that could have impacted the stock price.

Confusion among voters has grown as the advertising volume increases. Brian Galle, an economics professor at the University of California, Berkeley, who helped draft the proposal, said flyers claiming the tax would apply to retirement savings were not part of his original text. Ashley Craig, a volunteer for the pro-tax group Patriotic Millionaires, reported hearing similar complaints about secret provisions. She noted that any change to the tax requires a two-thirds majority in the assembly.

The campaign has exposed a divide within the Democratic Party. The state party endorses the tax, but Governor Gavin Newsom opposes it, calling it poorly written. Newsom warned that the tax could drive away billionaires, whose combined wealth is estimated at 2.3 trillion dollars. Xavier Becerra, the gubernatorial candidate, and Katie Porter also oppose the measure. McCuan described the vote as a test between progressives and moderates that could influence the 2028 presidential race.

Opponents are also funding two related ballot measures designed to limit state taxation. One bars new taxes on personal property or retroactive levies. The other requires state auditors to review the financial impact of tax measures before voters see them. If either measure receives more votes than the billionaire tax, it could effectively cancel the levy even if Proposition 40 passes.

A recent poll by the Public Policy Institute of California shows voters narrowly support the tax but also back the two protective measures. Mark Baldassare, the institute's statewide survey director, noted that only one-third of citizen initiatives typically pass. Suzane Jiminez, chief of staff at the SEIU health workers union, said 3,000 volunteers are currently canvassing. She cited support from Senator Bernie Sanders and Congressman Ro Khanna as key assets in the final week of the campaign.