Skip to navigationSkip to main contentADVERTISEMENTHal Bundrick, CFP® · Senior WriterUpdated Thu, June 18, 2026 at 4:36 PM GMT+2 5 min readBackers of a proposed tax on California billionaires have officially collected enough signatures to put the measure on the statewide ballot this fall, state officials say.However, with mounting opposition from high-profile politicians, including the state's governor, Gavin Newsom, and former presidential candidate Andrew Yang, the proposition might not make it to the ballot.The labor union Service Employees International Union-United Healthcare Workers West (SEIU-UHW) is spearheading a tax on the state's ultra-wealthy to prevent hospital and clinic closures, protect healthcare jobs, and help fund K-14 public education and state food assistance programs.Opponents say the tax would fuel an exodus of wealthy company founders and investors, spark job losses, and further weaken California's economy."I don’t think wealth taxes are a good idea in practice, and they’re definitely dumb at the state level," Yang posted on X.On Wednesday, California election officials confirmed that more than enough signatures were submitted for the petition seeking a state vote on the billionaire tax in November.What is the billionaire's tax?The proposed California tax act would levy a one-time 5% tax on the net worth of billionaire residents, subject to the asset restrictions noted below. Taxpayers could choose to pay the tax in five annual installments, with a 7.5% additional fee on the unpaid balance.Who would pay?Billionaires with primary residences in California as of Jan. 1, 2026, would owe the tax in 2027. That's an estimated 255 eligible taxpayers. A half-dozen or more high-profile tycoons relocated out of state as news of the proposed tax rolled out last year, so the number may be slightly lower.Those who have reportedly relocated include Google co-founders Larry Page and Sergey Brin.The tax proposal is not based on income — that's a loophole that allows billionaires to pay less in income taxes than the average American.Rather, the proposed California tax is based on billionaires' assets, including equity holdings, often in their own companies. The impact on the most wealthy would vary widely.For example, the Tax Foundation, a right-leaning tax policy nonprofit, projected that the tax would render Tony Xu, the founder of DoorDash, bankrupt, with a tax liability of $4.17 billion, unless he could challenge the initiative's asset valuation.On the other hand, Jensen Huang of Nvidia would face a tax liability of more than twice that: $8.5 billion.