Brin, Xu, and Tech Donors Outspend California Tax Backers 10 to 1

The campaign against California’s one-time billionaire tax has raised more than $300 million, making it the most expensive ballot measure fight in state history. David McCuan, a political science professor at Sonoma State University who tracks elections, confirmed the record spending as voters prepare to decide on November 3 whether to impose a 5 percent levy on the assets of the state’s wealthiest residents.

The opposition is funded by prominent technology leaders, including Google co-founder Sergey Brin, DoorDash founder Tony Xu, and Stripe co-founder Patrick Collison. Venture capitalists John Doerr, Michael Moritz, and Vinod Khosla have also contributed to the effort to block Prop 40. In contrast, supporters of the tax have raised only $32 million, creating a spending disparity of roughly ten to one.

The financial disparity has fueled confusion among voters, according to Brian Galle, an economics professor at the University of California, Berkeley, who helped draft the proposal. Galle noted that some flyers claim the tax could apply to ordinary residents and their retirement savings, a provision he said was not in the original text. Ashley Craig, a volunteer with the pro-tax group Patriotic Millionaires, reported that voters frequently ask about alleged secret provisions that would tax everyone. She stated that any modification to the tax would require a two-thirds majority in the state assembly and must align with the measure's original intent.

The spending reflects a deep divide within the Democratic Party. While the state party has endorsed the tax, Craig said ground support from the organization has been limited. McCuan described the measure as a proxy test between progressives and moderates. Governor Gavin Newsom, who is considering a 2028 presidential run, opposes the tax, calling it poorly written. He warned that the measure could harm the state if billionaires leave, estimating their total wealth in California at 2.3 trillion dollars. Gubernatorial candidate Xavier Becerra and former congresswoman Katie Porter also oppose the levy.

The opposition is backing two additional ballot measures. One would bar new state taxes on personal property or those imposed retroactively. The other requires state auditors to review proposed tax measures for financial impact before a vote. If either measure passes with more votes than Prop 40, it could effectively negate the billionaire tax even if voters approve it.

A recent poll by the Public Policy Institute of California found that voters narrowly support the tax but also back the two measures aimed at stopping it. Mark Baldassare, the institute's statewide survey director, noted that only about one-third of citizen initiatives pass, placing the burden of proof on the yes side. He plans to conduct another poll as voters receive official state guides explaining the measures.

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