Newsom Backs Brin-Funded Prop. 42, Which Would Block the Billionaire Tax and Ban Future Wealth Taxes

Gov. Gavin Newsom on Friday endorsed Proposition 42, the November measure bankrolled by Google co-founder Sergey Brin that is designed to cancel out Proposition 40, the proposed one-time tax on California billionaires.

Prop. 40 would levy a 5% tax on the assets of any billionaire who lived in California on Jan. 1, 2026, with 90% of the money going to Medi-Cal, the state's health program for low-income residents. Prop. 42 would bar most retroactive taxes and prohibit new state taxes on financial assets and other personal property. According to KQED's voter guide, if both pass and Prop. 42 gets more yes votes, the billionaire tax likely would not take effect.

A split with his party

CalMatters reported that the endorsement puts Newsom at odds with the California Democratic Party, which backs the billionaire tax, and with some labor unions. In a statement released by the measure's backers, who include police and fire unions, Newsom said Californians deserve to have their retirement and life savings protected from new state taxes.

Supporters of Prop. 40 pushed back hard. Debru Carthan of SEIU-United Healthcare Workers West, the union behind the billionaire tax, said in a statement that Newsom would rather see families lose health care than ask a few hundred billionaires to pay more. Rep. Ro Khanna, a South Bay Democrat campaigning for Prop. 40, has accused Newsom of siding with donors. CalMatters noted that Brin has never donated to Newsom, though the two have known each other for years.

The money gap is wide. The Associated Press reported that opponents of the billionaire tax have raised more than $300 million, close to a third of it from Brin, roughly 10 times what the yes side has raised.

The rest of the governor's list

Newsom announced positions on most of the 14 statewide measures. He opposes Prop. 39, the Republican-backed voter ID measure; Prop. 43, which would make most local taxes harder to pass; and Prop. 44, a health union measure setting how much clinics serving low-income patients must spend on care. A spokesperson said he has not yet taken a position on Prop. 41, a second Brin-backed measure aimed at the billionaire tax, and he has not weighed in on Prop. 45, a business-backed measure putting time limits on environmental review for new development.

Election Day is Nov. 3.