Six of California’s 214 billionaires have been widely reported to have left the state in time to avoid a proposed 5% wealth tax — but that small cohort would have collectively generated $27 billion in tax revenue, roughly a fourth of the initiative’s projected $100 billion haul.Last November, panic erupted over the announcement of a proposed billionaire’s tax in California. The tax would levy a one-time 5% tax on the net worth of California residents with assets worth at least $1 billion. California’s progressive governor, Gavin Newsom, emerged as the measure’s biggest opponent and vowed to stop the tax to “protect” the state’s tech industry and overall economy. Before the Jan. 1, 2026, cutoff proposed in the initiative, Google founders Larry Page and Sergey Brin, and venture capitalist Peter Thiel have left California for Miami. Car loan magnate and LA native Don Hankey left the state for Las Vegas. Former Uber CEO Travis Kalanick recently announced he had left California for Texas in December. Director Steven Spielberg became a New York City resident on New Year’s Day, according to the Los Angeles Times, although his representative said the Jaws director had long planned to move to be closer to family. The tally of departed billionaires likely understates the extent of the flight. Meta CEO Mark Zuckerberg has also reportedly left the state, but not before the Jan. 1 deadline. Venture capitalist David Sacks, whose net worth has been reported to range from $250 million to $2 billion, also left the state as his company Craft Ventures moved to Austin. Zuckerberg would take another roughly $10 billion of tax revenue with him. If the state were to tax Page’s $260 billion net worth at 5%, they would rake in $13 billion in tax revenue. Brin’s taxes would bring in about $12 billion. While Thiel, Kalanick, and Hankey may not rank among the top 5 richest men in the world, together they would have generated $1.775 billion. The loss of a fourth of the proposed tax revenue is a major hit to the initiative, which intends to use the funds toward healthcare, education, and food assistance. Billionaires are backing a fight Billionaires in and outside of California are working to fight the tax, which has been a harbinger for more wealth taxes across the country. Brin donated $20 million to a group called Building a Better California that is giving out $15 to people who sign their three countermeasures. The group’s proposals would prevent retroactive taxes and narrow the definition of California residency to fight against the 2026 Billionaire Tax Act’s application to anyone who lived in the state as of Jan. 1, 2026. Two billionaire-backed political action committees, Stop the Squeeze and Golden State Promise, have launched to stop the proposal. Chicago-based venture capitalist Daniel Tierney donated $200,000 to Stop the Squeeze, and crypto billionaire Chris Larsen is backing Golden State Promise, The New York Times reported. Since the California initiative was announced, other states have proposed higher taxes on their high-earning residents. In January, Rhode Island Governor Dan McKee backed a 3% tax increase on millionaires. Last week, Washington, which is one of nine states without an income tax, passed a 9.9% tax on personal income above $1 million per year. “We’ve got more millionaires and billionaires than we’ve ever had, and they’re paying, effectively, a 4% tax rate,” Rep. Brianna Thomas, a Democrat who supported the measure, previously told Fortune. “Meanwhile, you got working folks paying 11% of their income, and the lowest-income people paying 14%. Isn’t it unfair for those who have the most, to pay the least, and those who have the least to pay, the most, proportionally?”This story was originally featured on Fortune.com