A Wealth Tax on the November Ballot

California's Proposition 40 is a combined constitutional amendment and state statute set to appear on the state's Nov. 3, 2026 ballot. If voters approve it, California's billionaires would pay a one-time 5% tax on their accumulated wealth, with the revenue directed mostly toward state healthcare programs, along with smaller shares for food assistance and public education.

A new poll from the University of California, Berkeley's Institute of Governmental Studies, released Aug. 17, found 48% of likely voters supporting the measure and 41% opposed, with 11% still undecided. That represents a narrowing from a Public Policy Institute of California poll conducted May 14-18, which had found 54% support, including 76% support among Democrats.

The UC Berkeley poll also found that 72% of voters say they have already heard of the initiative — a notably high awareness figure for the middle of summer, well before the kind of campaign advertising that typically dominates the weeks before a general election. That level of early recognition typically reflects sustained news coverage and advocacy-group messaging rather than paid campaign advertising, which for most ballot measures does not ramp up in earnest until closer to Labor Day.

A Familiar Partisan Divide, Tightening

The polling breaks down largely along familiar partisan lines. Democrats and self-described liberals back Proposition 40 by wide margins, while Republicans and conservatives are strongly opposed, according to both polls. What has changed between May and August is not the direction of that split but its size — the six-point drop in overall support suggests that some voters in the middle, or some Democrats who initially leaned supportive, have moved toward opposition or undecided as the measure has gotten more attention.

That fight matters because of who the tax targets and how visible those targets are in California specifically. The state is home to a concentrated share of the country's technology and venture-capital wealth, meaning any framing battle over Proposition 40 will inevitably become a referendum on how voters view that particular slice of the ultra-wealthy, not billionaires in the abstract. A one-time 5% levy sounds narrow on paper, but the campaign fight over it is likely to turn on broader arguments about whether concentrated wealth in the state should be taxed differently at all — an argument that tends to harden existing positions rather than move persuadable voters, at least in a campaign's early innings. Because the tax is structured as one-time rather than recurring, supporters can frame it as a limited, one-off measure tied to a specific funding need, while opponents can just as easily frame any one-time wealth tax as a precedent that later becomes permanent — both framings can be argued from the same ballot language.

What Could Move the Needle Before November

Money is the first thing to watch. Ballot measures of this size typically draw heavy outside spending from both proponents — often labor and healthcare-advocacy groups, given where the revenue would go — and opponents, frequently business associations and individuals who would be directly subject to the tax. How much each side spends, and how early, will shape whether the current 11% undecided bloc breaks toward support or opposition.

The next test will be whether additional polling through September and October shows the gap continuing to narrow or stabilizing near its current level. A measure sitting at 48%-41% with 11% undecided is not a settled outcome in either direction — ballot measures on tax policy have historically been vulnerable to erosion in support as a campaign progresses and opposition spending increases, a pattern this measure would need to buck to pass in November. California's own ballot-measure history includes examples of tax initiatives that polled comfortably ahead in summer surveys only to finish much closer, or to fail outright, once general-election advertising began in earnest — a comparison worth keeping in mind given how far Proposition 40's support has already moved before that phase of the campaign has even started.