Opponents spent at least five times as much as supporters
An Associated Press race call indicated on Nov. 9, 2026, that California voters had rejected Proposition 40. The measure proposed a one-time 5% tax on most of the wealth held by billionaires in California. Supporters said it could raise $100 billion for health care, while opponents warned that the tax would prompt wealthy residents to leave the state.
Proposition 40 divided Democrats in California, where the party heavily outnumbers Republicans. The California Democratic Party backed the measure, as did Rep. Ro Khanna of California. Sen. Bernie Sanders of Vermont traveled to the state to campaign for it.
Democratic Gov. Gavin Newsom opposed the measure, saying a national tax on the wealthy would be better. Democratic gubernatorial candidate Xavier Becerra also opposed it. A leading teachers union opposed Proposition 40, which would have set aside just a small portion of the resulting revenue for schools.
SEIU-UHW, a union representing health-care workers, led the campaign in favor of the measure. Advocates said the proposal could raise $100 billion for health care. They argued that the Republican-controlled Congress had cut health-care programs to provide tax breaks to the wealthy and that it was time for wealthy Californians to fill the gap.
California had more than 200 billionaires, according to estimates, though some estimates put the number at a few hundred. Opponents argued that the proposal would drive wealthy residents out of California. They said that would cost the state revenue and harm the economy.
Google co-founder Sergey Brin led other wealthy Californians in a surge of campaign spending against the measure. At least five times as much was spent opposing Proposition 40 as favoring it.
Brin also drove a campaign behind two other proposals on the ballot. Those proposals sought to block the billionaire tax from taking effect even if voters had approved Proposition 40.