California voters will decide Nov. 3 whether to impose a one-time wealth tax on eligible billionaires, a ballot measure that could direct most proceeds to health care but has sharply disputed fiscal effects.
The measure would cover California-resident individuals on Jan. 1, 2026, and qualifying trusts connected to them. Net worth would be measured Dec. 31, 2026, with tax due in 2027. For individuals, the rate would phase up to 5% across net worth between $1 billion and $1.1 billion. Taxpayers could pay in five annual installments, with a 7.5% annual charge on deferred balances. Real estate, pensions and retirement accounts generally would be excluded.
After administrative costs, 90% of remaining proceeds would go to health care and 10% to education and food assistance.
California’s Legislative Analyst’s Office (LAO) projects temporary revenue in the tens of billions of dollars over several years, while warning that the total is difficult to predict. It also estimates a possible ongoing reduction of less than $1 billion a year in state income-tax revenue from billionaires.
A working paper by Jasper Boll, Emmanuel Saez and Gabriel Zucman estimates about $100 billion in proceeds. The authors count 250 California billionaires with combined wealth of $2.3 trillion as of July 1, 2026, using Forbes data, and assume 10% avoidance and evasion. The paper says Saez advised on the measure’s design without pay. The National Bureau of Economic Research (NBER) says its working papers are not peer-reviewed.
Joshua Rauh and four co-authors put potential receipts at about $40 billion before other tax-base effects in a Stanford-hosted working paper. Their model values projected income-tax losses tied to departures at $24.7 billion more than the one-time proceeds in net-present-value terms. Both papers offer estimates based on their own assumptions, not confirmed collections.
George Zimmer, founder and CEO of Generation Tux, endorsed the measure in a Nov. 2 opinion column published by The Guardian. He argued that billionaires able to contribute more have “a civic duty” and said the tax could support public services and reduce inequality. Zimmer also pointed to earlier state tax changes in challenging concerns about wealthy residents leaving. A report by the Institute for Policy Studies and State Revenue Alliance found millionaire populations grew 38.6% in Massachusetts and 46.9% in Washington from 2022 to 2024; those figures do not show how many people moved because of tax changes.
The LAO says Proposition 40 could still be blocked if Proposition 41 or Proposition 42 receives more “yes” votes. California’s vote is Nov. 3.
