California voters could face a ballot measure this November that would impose a one-time 5% tax on the wealth of billionaires living in the state, with the vast majority of the revenue directed toward health care services including Medi-Cal. The proposal, formally titled the 2026 Billionaire Tax Act, targets residents whose net worth exceeded $1 billion as of January 1, 2026, and has already drawn fierce opposition from federal lawmakers. With Medi-Cal consuming roughly 40% of state spending across all fund sources and federal financing rules tightening, the initiative arrives at a moment when California’s health care budget faces pressure from both ends.
What the Ballot Measure Would Do
The initiative would levy a one-time tax on billionaires living in California on January 1, 2026, with payments due beginning in 2027 and an option to spread payments over several years. The tax applies to “covered assets” valued above $1 billion, a category that, according to the California Secretary of State, includes businesses, securities, art, collectibles, and intellectual property. Real estate, pensions, and retirement accounts are excluded from the calculation, according to the California Legislative Analyst’s Office, which notes that the measure would function as a constitutional amendment limiting how future legislatures could alter or repeal it.
There is a subtle but meaningful distinction in how the tax is framed across official documents. The LAO describes it as a one-time 5% tax on residents with net worth over $1 billion, while the Secretary of State’s notice characterizes it as a tax of “up to 5%” on covered assets over that threshold. That difference matters for how much revenue the measure would actually generate and how courts might interpret its reach. Regardless of which framing prevails, 90% of the proceeds would be earmarked for health care services, creating a direct pipeline between billionaire wealth and programs like Medi-Cal. The remaining 10% would be set aside for administration and other specified uses, and the measure specifies that existing education funding guarantees would not apply to this money, insulating the new revenue from some of the state’s usual budget formulas.
A $100 Billion Revenue Estimate and Its Limits
An expert report published in late December 2025 by researchers at UC Berkeley projected that the proposed tax would generate $100 billion in additional revenue for the state of California for years 2027 and beyond. That figure is striking, but it rests on assumptions about asset valuations and billionaire residency that are inherently volatile. Several of the wealthiest people in the world live in California, according to the LAO’s analysis, which means the tax base is concentrated among a small number of individuals whose net worth can swing by tens of billions in a single quarter based on stock prices alone. Any downturn in technology markets or major relocation by a handful of ultra-wealthy residents could substantially shrink the projected haul.
The one-time structure of the tax introduces a separate challenge. A single revenue event, no matter how large, does not solve recurring budget gaps. Medi-Cal spending stands at nearly $200 billion across all funds, with General Fund spending alone reaching $44.9 billion in 2025-26, roughly 20% of the state’s General Fund. Even a $100 billion windfall, with 90% directed to health care, would cover only a few years of General Fund Medi-Cal costs before the money runs out. Proponents would need to explain how the state avoids a fiscal cliff once the one-time infusion is spent, particularly if new programs or expanded coverage are built on top of it. The measure does not itself create a permanent revenue stream, so long-term sustainability would depend on future legislative choices, economic growth, or additional tax changes.
Federal Pressure on Medi-Cal Financing
The billionaire tax proposal does not exist in a vacuum. More than half of Medi-Cal’s funding comes from federal sources, and those dollars face growing scrutiny. The Centers for Medicare and Medicaid Services issued a final rule targeting certain Medicaid financing arrangements that CMS described as a loophole costing federal taxpayers in the tens of billions annually. That rule aims to restrict how states use provider taxes and supplemental payments to draw down federal matching funds, a mechanism California has relied on heavily to support hospitals, nursing homes, and other safety-net providers without raising visible taxes on residents.
If federal matching rates decline or financing flexibility narrows, the state’s share of Medi-Cal costs rises. That dynamic gives the billionaire tax a different political valence than it might otherwise carry. Advocates can argue that state-generated revenue becomes more important precisely because Washington is pulling back, positioning the tax as a way to stabilize coverage for low-income residents, children, and people with disabilities. Critics counter that a one-time tax is the wrong tool for an ongoing structural problem, and that the measure could accelerate the departure of the very residents whose income and capital gains taxes already fund a large share of the California state budget. No official state economic modeling on potential billionaire migration has been published, leaving that argument in the realm of speculation rather than evidence, but the possibility of behavioral responses looms over the debate.
Congressional Opposition Takes Shape
The political fight over the measure has already jumped from Sacramento to Washington. Rep. Kevin Kiley, a Republican representing California’s 3rd Congressional District, introduced a federal bill in February 2026 aimed at blocking the state tax. Kiley’s framing characterizes the measure as one that would “confiscate” 5% of wealth over $1 billion, language designed to cast the initiative as a constitutional overreach rather than a standard tax policy question. His proposal would bar states from imposing wealth taxes of this kind, arguing that such levies undermine property rights, discourage investment, and invite legal battles over interstate commerce and federal supremacy.
The bill’s prospects in Congress are uncertain, and even if it advanced, it would almost certainly face court challenges over federal authority to preempt state tax powers. Still, the move signals that opponents intend to fight the measure on multiple fronts: in the courts, in Congress, and at the ballot box. For supporters, that national spotlight could be a double-edged sword, elevating the campaign’s profile and fundraising potential while also galvanizing well-funded opposition from business groups and anti-tax organizations. As signature gathering proceeds and legal analyses proliferate, voters will be asked to weigh not only the promise of a large but fleeting revenue surge for health care, but also the broader precedent of taxing wealth itself, rather than the income it generates.
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*This article was researched with the help of AI, with human editors creating the final content.
Julian Harrow specializes in taxation, IRS rules, and compliance strategy. His work helps readers navigate complex tax codes, deadlines, and reporting requirements while identifying opportunities for efficiency and risk reduction. At The Daily Overview, Julian breaks down tax-related topics with precision and clarity, making a traditionally dense subject easier to understand.
