California Wealth Tax Loses Support as Opposition Spending Grows

California's proposed billionaire wealth tax is losing voter support as the Nov. 3 election approaches, with opposition campaign spending far exceeding contributions from supporters. A UC Berkeley Institute of Governmental Studies poll co-sponsored by the Los Angeles Times found that 50% of likely voters oppose Proposition 40, while 42% support the measure, which would impose a one-time tax on billionaire assets to help fund healthcare programs.

The findings represent a reversal from a September survey in which Proposition 40 held a narrow lead. The latest results also align with a Public Policy Institute of California poll released Tuesday, which found that 52% of likely voters opposed the proposal and 46% supported it, according to the respective polling organizations.

Campaign finance figures underscore the disparity between the two sides. Nearly $368 million has been contributed to efforts opposing Proposition 40, compared with $36 million donated in support, according to the Los Angeles Times. Opposition advertising has appeared across television and social media, including during NFL games and reruns of television sitcoms.

Proposition 40 would establish a one-time 5% tax on the assets of billionaires who resided in California as of Jan. 1, with certain exceptions. The proposal was developed by the Service Employees International Union-United Healthcare Workers West to help offset an estimated $100 billion in federal healthcare cuts approved by President Trump and congressional Republicans.

Mark DiCamillo, director of the UC Berkeley poll, said opposition has expanded across major voter groups as election day nears. The September survey had shown the measure narrowly ahead, making the subsequent decline significant.

"It's below 50%, and it's trending down. Both of those are ominous signs," DiCamillo said.

Democratic voters remain divided over the proposal. Nearly two-thirds of Democrats support it, while more than a quarter oppose it, according to the poll. Republicans overwhelmingly oppose the tax. Voters also differ by age: six in 10 voters aged 65 or older oppose the measure, while more than two-thirds of voters under 30 support it.

Gov. Gavin Newsom opposes Proposition 40, warning that wealthy residents could leave California and further destabilize a state budget heavily dependent on high-income taxpayers. The California Democratic Party and prominent progressive advocates support the proposal, including Sen. Bernie Sanders (I-Vt.), who has argued that the tax could help residents affected by federal healthcare reductions.

Opponents have also backed Propositions 41 and 42, two measures designed to limit taxation and potentially nullify Proposition 40 if either receives more votes than the wealth tax proposal. Proposition 41 would require audits of new state special taxes and restrict taxes exempt from the state's spending limit. Proposition 42 would prohibit new taxes on retirement holdings, individually owned assets and other personal savings.

The same Berkeley-Los Angeles Times poll found that 38% of likely voters support Proposition 41, while 47% oppose it. Proposition 42 receives 43% support and 45% opposition, reversing an earlier advantage in September. DiCamillo said opposition was particularly strong among voters who understood that the measures could block the billionaire tax.

A separate debate concerns how broadly California should tax wealth. An Oct. 29 New York Times opinion article argued that Proposition 40 focuses too narrowly on billionaires while overlooking other affluent households. The authors estimated that California had approximately 450,000 households owning private businesses and holding at least $5 million in wealth at the end of 2025, with combined wealth of about $9 trillion, compared with approximately $2 trillion held by the state's billionaires.

Steven Malanga, a senior fellow at the Manhattan Institute writing in City Journal on Oct. 28, argued that the California campaign could influence wealth-tax proposals elsewhere, regardless of the election outcome. He cited proposals in Minnesota, Illinois, Maryland and Washington state, although several had not advanced through their respective legislative processes.

California voters also expressed stronger support for Proposition 3, which would make permanent a higher income tax rate on wealthy residents that funds education. The Berkeley-Los Angeles Times poll found that 54% support extending the existing levy and 37% oppose it. DiCamillo attributed the difference partly to the tax already being in place and its established revenue contribution, which he said could preserve $5 billion to $15 billion in annual funding.