California Proposition 40: Inside the $100 Billion Billionaire Wealth Tax on the November Ballot

A one-time 5% levy on the net worth of California’s roughly 250 billionaires heads to voters this November as Proposition 40, setting up a direct collision between the nation’s wealthiest residents and a state healthcare system reeling from federal funding cuts.

If approved, the measure is projected to generate approximately $100 billion. Ninety percent of that revenue would be directed toward healthcare services, with the remaining funds allocated to education and food assistance programs. The initiative bypasses the state legislature entirely, utilizing California’s direct democracy framework—a system established by progressive-era reformers in 1911 specifically to counter corporate influence over state government.

The push for a state-level wealth tax arrives as California hospitals brace for severe financial strain. Federal budget reductions enacted under the Trump administration have already stripped Medi-Cal coverage from more than 200,000 Los Angeles County residents. Researchers at UC Berkeley project that figure could surpass 1 million statewide by 2028. Public Citizen, a consumer advocacy organization, recently identified more than 80 California hospitals facing heightened operational risk due to these federal cuts, with over 20 located in L.A. County alone.

The economic fallout extends beyond hospital balance sheets. Advocates backing the proposition cite estimates that every dollar lost in Medi-Cal funding drains $1.85 in local economic output. In L.A. County, that dynamic threatens more than 63,000 jobs and $9 billion in broader economic activity.

Wealth concentration among California’s ultra-rich has accelerated sharply over the past decade. A group of six Nobel Prize-winning economists recently published a letter endorsing the measure, noting that the combined net worth of the state’s billionaires has surged 220%—from $700 billion to an estimated $2.3 trillion. The laureates argued that this accumulation stems not solely from innovation but from systemic failures to tax returns on capital. They also pointed out that billionaires accounted for 19% of all federal election donations during the 2024 cycle, a figure underscored by Elon Musk’s individual contributions exceeding $290 million.

Opponents argue the tax will trigger a mass exodus of high-net-worth individuals. However, labor economist Teresa Ghilarducci has challenged this assumption, pointing out that billionaires are deeply embedded in local economies, business networks, and real estate markets. Academic research on previous state-level tax increases targeting millionaires, including studies examining New York’s 2009 millionaire tax surcharge, generally shows that migration responses among the wealthy are significantly smaller than critics predict.

Implementing a tax on net worth rather than income introduces distinct administrative hurdles. Unlike realized income, assets such as private equity stakes, art collections, and closely held businesses lack daily market prices, requiring complex valuation frameworks. Dan Walters of CalMatters recently described the mechanics of the proposal as “confounding,” noting that opponents have placed competing measures on the same ballot to muddy the waters. Legal challenges are widely expected if the proposition passes, likely testing constitutional questions around whether states can levy taxes on assets held outside their borders.

Gov. Gavin Newsom has publicly opposed the initiative, arguing that wealth taxation should be handled at the federal level. Yet the current political environment in Washington makes congressional action on billionaire taxation highly improbable. Historically, major American social policies—including unemployment insurance, workers’ compensation, and maternal healthcare programs—were pioneered by state legislatures decades before Congress adopted them nationally.

The Franchise Tax Board, which would be tasked with administering the levy, currently oversees the personal income tax system that already relies heavily on top earners. Because California uses a volatile capital-gains-dependent tax structure, revenues swing wildly with stock market performance. Proposition 40 represents a structural departure from that model, attempting to capture stored wealth rather than annual income fluctuations.

Campaign finance filings show opposition committees funded by tech executives and venture capitalists have begun reserving advertising slots across Southern California media markets ahead of the November vote.