The California One-Time Wealth Tax for State-Funded Health Care Programs Initiative, also referred to as the California billionaire tax, is a combined initiated constitutional amendment and state statute proposed for the November 3, 2026, ballot in the state of California.
If approved and passed, the state's billionaires would pay a one-time 5% tax on their accumulated wealth to fund health care programs, food assistance and public education.
SEIU United Healthcare Workers West filed the initiative, which was drafted by Brian Galle of the University of California, Berkeley, David Gamage of the University of Missouri, and Darien Shanske of the University of California, Davis, citing research by Gabriel Zucman and Emmanuel Saez. In December 2025, state attorney general Rob Bonta issued the official title and summary.
The initiative would impose the Billionaire Tax Act, a one-time 5% tax on the net worth of the California residents worth over $1,000,000,000USD. The tax would be used to fund state-funded healthcare programs, including Medi-Cal, as well as state food assistance and public education.
The eligibility cut-off outlined in the initiative was January 1, 2026, meaning that if the initiative is certified for the ballot and passed by voters, billionaires who continued to hold residence in the state of California after that date will be subject to the 5% tax. At least six of the state's estimated 214 billionaires left California before the deadline, including Google co-founders Larry Page and Sergey Brin and former Uber CEO Travis Kalanick. In February 2026, entrepreneur Chamath Palihapitiya estimated that over $700 billion was transferred out of California after the initiative was announced.
Labor union SEIU United Healthcare Workers West, who helped propose the initiative, estimated that the tax would generate $100 billion, though the six known billionaires who left the state before the deadline would have contributed more than a quarter (an estimated $26.775 billion) of that amount. Academic Kent Smetters cast doubt on the SEIU's estimate, telling the Los Angeles Times that the union is "not accounting for the different ways that people can move their wealth."
The Tax Foundation argued that the effective tax rate could far exceed 5% for some taxpayers due to provisions related to dual-class share structures, while Hoover Institution estimated that "permanent loss of income taxes from the departing residents indicates a high likelihood that net effect of the Billionaire Tax Act will be negative" by almost $25 billion. In response to the initiative, activists staged a pro-billionaire protest march in San Francisco on February 7, 2026.