See more of our coverage in your search results.

California plans to come after the super-rich residents who fled the state to avoid its proposed billionaires tax.

Heavy hitters like Google co-founder Sergey Brin, venture capitalist and White House advisor David Sacks, and Uber co-founder Travis Kalanick should expect the Golden State to perform intrusive residency audits to determine whether the ultra-wealthy businessman still call California home, according to the Financial Times.

It could cost the the trio billions of dollars if they can’t provide a convincing case to California that they no longer hold residency in the state. All three relocated last year after the proposed 5% billionaires tax came under consideration.

Brin, who owns the title of the third-richest person in the world with a $270 billion net worth, reportedly purchased a mansion on the Nevada side of Lake Tahoe in December and listed Nevada as his home state in a campaign finance filing this year.

Pat Dwyer, co-founder of Aligned Wealth and a financial adviser to the super wealthy, compared the potential battle to a “game of chess.”

“Residency is murky and California are really tough, along with New York, in looking at more than just time spent in the state to decide whether you really live there,” he told the Financial Times. “It’s like a game of chess, your lawyers against their lawyers, and it’ll end up in court.”

The state’s California Franchise Tax Board will investigate whether ultra-rich former residents have sufficiently cut ties to the state.

A handbook for its staff says the board will test whether each billionaire “substantially severed his California connections upon his departure or whether he maintained his California connections in readiness for his return.”

The process includes looking into whether the person’s children are still enrolled in schools in the state, where their cars are registered, and where they have doctors, veterinarians or bank accounts.

Those who fled the state need to make a convincing case all around, said Darien Shanske, a professor at University of California Davis School of Law.

“Sending your assistant to get a driving licence in Nevada, spending Christmas at your home in Miami and writing a mean tweet about California are only moves on paper,” he told the Financial Times.

Billionaires like Brin have funded efforts to defeat the wealth tax, including a proposal to audit programs funded by any new taxes.

“Sending your assistant to get a driving licence in Nevada, spending Christmas at your home in Miami and writing a mean tweet about California are only moves on paper,” he told the Financial Times.

Wealthy people are prepared to challenge the tax if it is passed in a November statewide referendum, but they should expect a fight.

“If the tax goes through, the [Franchise Tax Board] will not be afraid to try to collect it,” Alex Kugelman, a San Francisco Bay Area tax attorney, told the outlet. “And obviously people of that means will have the top tax litigators. These fights will go all the way.”

The tax would impact anyone with a wealth above $1 billion and would be retroactive to anyone residing in the state as of January 1, 2026. Most of the money raised by the tax, if approved by voters, will go toward healthcare and education.