2026-10-31 · contested story
California Prop 40: one-time 5% billionaire tax for healthcare faces $300M fight
California voters are deciding on Proposition 40, a first-in-the-nation ballot measure that would impose a one-time 5% tax on the net worth of the state's roughly 200-250 billionaires, with 90% of the estimated $100 billion in revenue directed toward healthcare to backfill federal Medicaid cuts from Trump's 'One Big Beautiful Bill.' The measure, drafted by SEIU-United Healthcare Workers West, has triggered the most expensive ballot fight in California history—opponents led by Google co-founder Sergey Brin have raised over $300 million, while supporters raised roughly $32-40 million. The fight has split Democrats, with Gov. Gavin Newsom opposing it (while endorsing a national alternative) and Sen. Bernie Sanders and Rep. Ro Khanna championing it. Polls show support slipping below a majority as Election Day nears.
How each side frames it
left
"California billionaires cry over possibility of paying their share"
"The 22 billionaire snowflakes include a bunch of tech bros and crypto barons making billions off developing an AI future for the rest of us."
"US voters have an opportunity to beat back the forces of fascism and confront the billionaires who are rigging the economy, our media system, and our democracy"
"We can either be a Democratic Party that stands for the working class in the tradition of the New Deal, or we can continue to cater to the donor class"
"Earning his French Laundry reputation, Newsom is also currently pushing separate ballot measures to permanently ban such wealth taxes on billionaires in the future."
center
"If I was a California voter and I didn't have any training in economics or anything like that, I would be very confused... I would not really know what to think."
"Among 105 respondents, 69.5 percent opposed the proposal, including 71.0 percent of economists and 85.0 percent of accountants. Lawyers were more supportive, with 60.0 percent favoring the tax."
"There's going to be some kind of economic consequences, and whether you think those consequences are good or bad, and how bad you think they are, depend upon what you value"
"Suppose that formula values a private company at $2 billion. Its founder holds 10 percent of the economic interest but controls 60 percent of the votes... The same company could produce a sixfold difference in the founder's presumed taxable interest"
"We have abundant evidence from other taxes on the wealthy in the U.S. and abroad, that wealthy people often say they're going to leave and then don't"
right
"California Risks Killing the Golden Goose With Proposition 40"
"I fled socialism with my family in 1979 and know the devastating, oppressive society it created in the Soviet Union. I don't want California to end up in the same place."
"advocates say it will do no harm because it is a one-time event... But that's only true if people believe it is a one-time event. If they think, 'Hey, there's no Santa Claus, and no Easter Bunny, I bet there's no one-time money grab.'"
"It's sheer robbery."
"publicly confirmed departures already eliminated nearly 30 per cent of the wealth tax base before signatures were collected"
What each side left out
The left left out — covered by the The Daily Economy & TaxProf Blog & TechCrunch
- The administrative/valuation difficulty of taxing illiquid private company stakes and the sixfold voting-vs-economic ownership discrepancy
- The UNC/National Tax Association survey finding ~70% of tax scholars oppose the measure
The left left out — covered by the Fox Business & City Journal & CBS News
- The Legislative Analyst's Office estimate of ongoing income-tax revenue losses and administrative costs of tens of millions per year
The right left out — covered by the Daily Kos & otherwords.org & CBS News & Democracy Now!
- That billionaires like Nvidia's Jensen Huang, Tom Steyer, Scott Kirby, and Palmer Luckey publicly support or accept the tax, with Huang calling it 'a privilege'
- That California's venture capital and billionaire count actually rose after the tax was announced (per Khanna/Acemoglu)
The right left out — covered by the Mother Jones & HuffPost & PBS NewsHour
- Data showing billionaires pay low effective tax rates (0.26% of wealth annually in state income tax; 24% federal average per Zucman/Saez) and the 'buy-borrow-die' mechanism
The center left out — covered by the The Boston Globe & The Guardian & Common Dreams
- The explicit anti-oligarchy / democracy-vs-plutocracy political framing that motivates many supporters
The left left out — covered by the WIRED & CBC
- The Zuckerberg deal requiring him to stay only 'wherever Meta maintains its headquarters' — meaning both he and Meta could still relocate together
What's actually true?
[verified] Proposition 40 would impose a one-time 5% tax on the net worth of California residents worth more than $1 billion who lived in the state as of January 1, 2026, with revenue (90%) directed mostly to healthcare.
[verified] Sergey Brin has contributed at least $102 million to oppose Prop 40, and opponents have raised over $300 million total across the three related measures.
[contested] The Stanford/Hoover (Jaros and Rauh) working paper estimates the tax would collect roughly $28-36 billion and project an average net fiscal loss of about $38.9 billion in present value due to departing billionaires.
[verified] California's nonpartisan Legislative Analyst's Office estimates the tax would raise tens of billions over several years but cause an ongoing income-tax revenue loss of less than $1 billion per year.
[verified] Mark Zuckerberg struck a deal with Meta's board to receive new non-voting shares he can sell to pay a potential ~$11-12.5 billion tax bill, in exchange for committing to remain a California (or Meta HQ) resident for eight years.
[verified] Polling showed support for Prop 40 declining from a 52% majority in September to 46% (or below majority) by late October, with 52% opposed in the final PPIC poll.
[verified] A survey of 105 tax scholars found 69.5% would vote against Prop 40, including 71% of economists and 85% of accountants, while 60% of lawyers favored it.
[verified] Six Nobel Prize-winning economists (including Acemoglu, Krugman, Stiglitz) signed a letter in September supporting the proposal as the 'first opportunity for the people to start reining in the power of billionaires.'
The narrative clash
How much revenue the tax will raise
Left: Supporters of the proposal, championed by the SEIU-United Healthcare Workers West union, estimate it would raise $103 billion in revenue
Right: a new study finds that the measure would bring in about $40 billion—less than half the estimated $100 billion collection
Whether the tax will net lose money for California
Left: no, billionaires won't all flee, and yes, they can pay their fair share without losing their companies
Right: the Golden State stands to lose nearly as much as $4.5 billion per year from billionaire flight, quickly offsetting any fiscal benefit the one-time wealth tax might bring
Whether billionaires are actually leaving
Left: California actually has increased billionaires since Proposition 20... We've gone from 240 billionaires to 261 billionaires. Eighty-five percent of the venture capital has come into California
Right: By January 1, six publicly confirmed departures—Thiel, Page, Google co-founder Sergey Brin, film producer Steven Spielberg, financier Don Hankey, and venture capitalist David Sacks—removed an estimated $536 billion in wealth from California's tax base
Validity of the Hoover/Stanford capital-flight study
Left: It's absurd slop
Right: They modeled 100,000 scenarios and 85% of them found a negative impact on state revenue
Whether capital flight is real or a bluff
Left: Billionaires' threats to leave are theatrics; the empirical record and Zuckerberg's stay-in-California deal show they mostly don't move.
Right: The flight has already happened — a large share of the taxable base departed before the measure even qualified for the ballot.
109 sources analyzed
The Boston Globe NPR Bloomberg Government News Just The News City Journal Common Dreams Al Jazeera Pacific Research Institute Just The News City Journal Daily Kos NPR CNBC Just The News The Daily Signal HuffPost The Washington Post Straight Arrow Reason Magazine City Journal The Boston Globe Capital & Main Truthout Just The News City Journal Mother Jones Business Insider Democracy Now! The Center Square National Review Mother Jones CBC Macau Business RealClearMarkets The Daily Signal The Boston Globe PBS NewsHour otherwords.org New York Post City Journal Common Dreams NBC News BBC Manhattan Institute National Review The American Prospect Los Angeles Times TaxProf Blog Fox Business Washington Examiner Mother Jones The Washington Post The Daily Economy Investor's Business Daily Fox News Common Dreams NBC News The American Action Forum National Post The Daily Signal Common Dreams The Guardian FlowingData Orange County Register The Daily Signal Common Dreams The New York Times CalMatters Investor's Business Daily National Review Mother Jones NBC News Seoul Economic Daily Richmond Times-Dispatch National Review MSNBC PBS NewsHour CBS News Richmond Times-Dispatch National Review MSNBC NBC News The Lever Investor's Business Daily San Francisco Chronicle Politico KQED Richmond Times-Dispatch MSNBC The Washington Post Ynetnews Investor's Business Daily The Mercury News Tax Foundation The Telegraph PBS NewsHour Pasadena Star News PBS NewsHour The Capital Times WIRED Yahoo Finance Sacramento Bee MyNorthwest.com The Washington Post Billionaires.Africa The Washington Post Noozhawk U.S. News & World Report TechCrunch