California voters are set to decide on a proposed billionaire tax as new IRS data shows continued taxpayer outflow from the Golden State, with Los Angeles County leading the nation in net filer losses and nearly $1.9 billion in income leaving for other states.
The ballot initiative, backed by the Service Employees International Union, qualified for the November election and would impose a one-time 5% wealth tax on residents with a net worth exceeding $1 billion. The measure would apply retroactively to Californians who were residents as of Jan. 1, 2026.
Supporters argue the tax could generate billions of dollars for healthcare and education programs, while critics warn it could accelerate departures of wealthy residents and drive investment elsewhere.
What the Left Is Saying
Democratic Rep. Ro Khanna of California has defended the proposed measure, arguing that billionaires should contribute more to the communities where they built their wealth. The proposal represents an effort to address what supporters characterize as tax fairness gaps in California's system.
The Service Employees International Union, which backed the initiative, argues that ultra-wealthy residents can afford to pay more and that revenue from the tax could fund critical services. Supporters contend the retroactivity provision ensures those who benefited from California infrastructure while accumulating wealth would contribute their fair share.
Progressive groups supporting the measure have pointed to polling showing broad public support for taxing extreme wealth, arguing that the proposal reflects voter priorities rather than special interests.
What the Right Is Saying
Billionaire investor Mark Cuban has emerged as a vocal critic of the proposal, warning it could drive not only wealthy residents but also investment and startups out of California. Cuban wrote on social media: "If this passes, and it doesn't directly impact me at all, I won't be a Cali resident, but you can bet if I'm investing in a multi billion dollar startup, I'm asking them to move from California first."
He added: "IMO, if this passes, only idiot startup founders stay in Cali," suggesting the measure could reshape where entrepreneurs choose to establish businesses.
Business groups and fiscal conservatives argue that taxing accumulated wealth rather than income creates unpredictable precedent. They warn that retroactive taxation could face legal challenges and damage California's reputation as a place for entrepreneurship. Critics also note that wealthy residents leaving means their future tax contributions, which would likely exceed any one-time wealth tax, depart with them.
What the Numbers Show
IRS data compiled from federal tax returns shows significant taxpayer outflow from California counties: Los Angeles County lost a net 17,496 tax filers, taking nearly $1.9 billion in income to other states; Orange County recorded a net loss of 11,618 filers; San Diego County lost 9,401 filers; Riverside County lost 8,968; and San Bernardino County lost 8,462.
These outflows predate the current billionaire tax debate but add context to discussions about California's ability to retain high-income residents. The movement of taxpayers affects state and local tax collections that fund schools, public safety, and infrastructure.
The proposed tax would apply only to residents with net worth exceeding $1 billion at a rate of 5% on their total wealth, generating an estimated one-time windfall for the state if upheld in court.
The Bottom Line
California's billionaire tax will appear before voters in November, representing one of the most significant tests of taxing extreme wealth at the state level. Supporters say it addresses fairness concerns and generates needed revenue; opponents argue it risks accelerating wealth flight that already challenges the state's fiscal base.
The debate arrives as IRS data shows continued net losses of high-income taxpayers from major California counties. What happens next will depend partly on whether courts uphold the retroactivity provision and whether promised revenues materialize if the measure passes. Both sides are watching closely as other states consider similar proposals.