Sergey Brin Spends Over $100 Million to Fight California Billionaire Tax
Sergey Brin has spent over $100 million fighting California Prop 40, a one-time 5% wealth tax that could cost him an estimated $13.3 billion tax bill.
Summary
An August 10, 2026 filing shows Google co-founder Sergey Brin donated another $20 million to Build a Better California, taking his spending against California’s proposed Prop 40 above $100 million. Brin, the world’s fourth-richest person with about $267 billion, could owe an estimated $13.3 billion. Prop 40 would impose a one-time 5% net-worth tax on roughly 200 California billionaires, directing most proceeds to healthcare as the state’s Medicaid program faces up to $30 billion in lost federal funding when President Trump’s budget cuts take effect next year.
Meta founder Mark Zuckerberg reportedly bought a $170 million mansion near Miami this year, while former Uber CEO Travis Kalanick, venture capitalist Peter Thiel and Google co-founder Larry Page have left California. Governor Gavin Newsom, a California Democrat, opposes Prop 40 over risks that billionaires and businesses will flee, instead advocating a national billionaires’ tax and an end to stock-backed loans that let wealthy borrowers report no taxable income while office workers can pay higher rates than heiresses. Californians vote in November, while Build a Better California has proposed competing ballot measures that could block Prop 40 by restricting new taxes. Nvidia co-founder Jensen Huang, who could owe about $8 billion, told Bloomberg in January that he had not worried about the levy and accepted whatever taxes accompany living in Silicon Valley.
Positives
- Prop 40 would direct most proceeds from its one-time 5% levy toward California healthcare programs.
- Nvidia co-founder Jensen Huang said he is comfortable paying the approximately $8 billion he could owe.
- Governor Gavin Newsom supports a national billionaires’ tax and ending stock-backed borrowing that can produce no taxable income.
- California voters will decide Prop 40 in November rather than leaving the proposal solely to lawmakers.
Risks & concerns
- Sergey Brin has spent more than $100 million opposing a tax that could cost him an estimated $13.3 billion.
- California Medicaid could lose up to $30 billion in federal funding when President Trump’s budget cuts take effect next year.
- Travis Kalanick, Peter Thiel and Larry Page have left California, while Mark Zuckerberg reportedly bought a $170 million Miami-area mansion.
- Governor Gavin Newsom warns that Prop 40 could drive billionaires and their businesses out of California.
- Build a Better California has proposed competing measures that could effectively block Prop 40 by limiting new taxes.