By Rajwa Quasim
Google co-founder Sergey Brin has now contributed more than $100 million to Build a Better California, including the recent $20 million contribution in efforts to oppose the California’s proposed billionaire tax.
Building a Better California is an advocacy group with an associated PAC founded with $35 million in funding from Brin, former Google CEO Eric Schmidt, and other billionaires to combat the proposed tax on the wealth of billionaires.
If the proposed billionaire tax comes into effect, Brin — the world’s fourth-richest — must pay around $13.3 billion as tax from his net worth of $267 billion.
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Proposition 40, also known as the California billionaire tax or wealth tax, will appear on the state’s Nov. 3, ballot. If approved, it would impose a one-time 5% tax on the accumulated wealth of California billionaires. The estimated revenue from the tax is around $100 billion, which most would go towards state healthcare programs and additional funding for food assistance and public education. The initiative was sponsored by the labor union SEIU United Healthcare Workers West (UHW) and drafted by tax law professors after conducting research showing that billionaires paid lower effective tax rates than middle-class workers. This could overcome the financial strain which could be created once Trump’s budget cuts take effect next year.
SEIU-UHW offered to withdraw the 5% proposal if California Gov. Gavin Newsom supported a smaller 2% tax on billionaires through the state legislature. But Newsom rejected the proposal.
In June, several organizations and labor unions spoke out against the proposed billionaire tax. Groups such as Planned Parenthood and the California Medical Association criticized the move, describing it as a “flawed response” to cuts in healthcare funding. The California Teachers Associations also argued that the proposed tax would not provide schools and communities with stable and long-term funding. They also argue that this could discourage investment and in turn encourage wealthy residents to move out of California.
As per TechCrunch, Zuckerberg reportedly bought a $170 million mansion near Miami this year. Former Uber CEO Travis Kalanick, venture capitalist Peter Thiel, and Brin’s fellow Google co-founder Larry Page have also left the state.
In his Substack account, Newsom explicitly said he supported a national billionaires’ tax. He wrote that wealth should be taxed at the federal level as billionaires can easily move to states with a lower tax regime. “A modern Buffett Rule — that ensures the people at the very top pay at least the tax rate their own workers pay. Today, the office worker can shoulder a higher tax rate than the heiress. The construction worker could pay a higher rate than the developer. And the delivery driver can end up paying a higher rate than the founder of the company whose packages he delivers. […] We should end the ‘tax-free lifestyle loan,’ the gimmick that lets the ultra-wealthy borrow against their stock portfolios while reporting no taxable income,” he wrote.
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Senator Bernie Sanders and U.S. Secretary of Labor Robert Reich endorsed the proposed billionaire tax. Reich said, “practical way to keep the healthcare system functioning”.
“I have not even thought about it once. We chose to live in Silicon Valley, and whatever taxes they would like to apply, so be it. I’m perfectly fine with it,” said Nvidia CEO Jensen Huang.


