California's Billionaire Tax Act: What You Need to Know About the 2026 Wealth Tax Ballot Measure

California voters will decide in November 2026 whether to impose a one-time 5% tax on the total wealth of the state's billionaires, a measure known as the Billionaire Tax Act. The initiative was sponsored by SEIU United Healthcare Workers West, a major labor union, which submitted more than 1.6 million signatures in support of the measure, nearly double the 874,641 valid signatures required to qualify for the ballot. The California Secretary of State had until June 25, 2026 to certify that the signatures were valid and officially place the measure before voters. If passed, the tax would apply to any billionaire who was a California resident as of January 1, 2026, and 90% of the revenue generated would go toward state healthcare programs like Medi-Cal with the remainder directed to food assistance and public education. Early polling showed roughly 52% of California voters inclined to support the measure and 33% opposed, suggesting it enters the campaign season with meaningful but not overwhelming public support.

Supporters of the Billionaire Tax argue that a one-time levy on the ultra-wealthy is the most direct way to close the widening gap between the richest Californians and everyone else while protecting essential public services. The measure has drawn backing from prominent progressive figures including Senator Bernie Sanders and Representative Ro Khanna, as well as organizations like the Teamsters union, the California Democratic Socialists of America, and the group Our Revolution. Proponents point to deep federal cuts to Medi-Cal as a primary motivation, arguing that the wealth tax is the only realistic way to fill a funding gap that threatens health coverage for millions of low-income Californians. Supporters also note that taxing accumulated wealth rather than income addresses a structural flaw in the tax system, since the wealthiest individuals often pay relatively low income tax rates while their net worth grows through rising asset values. The SEIU committed $25 million to campaigning for the measure, signaling that organized labor intends to make this a centerpiece of its political agenda heading into the 2026 election.

Opponents of the measure argue that a wealth tax would push billionaires and their investment capital out of California, shrinking the tax base and ultimately costing the state more in lost income tax revenue than it gains from the one-time levy. California Attorney General Rob Bonta acknowledged in an official analysis that while the tax would produce a temporary revenue increase, it would likely cause an ongoing decrease in state income tax revenues of hundreds of millions of dollars or more per year as wealthy residents restructure their affairs or relocate. Tech billionaires including Sergey Brin and Peter Thiel have poured millions of dollars into the opposition campaign, framing the measure as an attack on innovation and entrepreneurship. Critics also raise constitutional questions about whether a state can tax wealth accumulated before the law was passed, since the measure is retroactive to January 1, 2026, and legal challenges are widely expected if the initiative passes. In an unusual coalition, Governor Gavin Newsom joined several left-leaning groups in opposing the measure, arguing that a poorly designed wealth tax could do lasting damage to California's fiscal health and its reputation as a home for business.