Google co-founder Sergey Brin has donated another $20 million to Build a Better California, an organization advocating against California’s proposed billionaire tax, according to a new filing. That means that the world’s fourth-richest man, whose net worth hovers around $267 billion, has now spent more than $100 million to avoid an estimated $13.3 billion tax payment.

California’s Prop 40, known as the billionaire tax, would impose a one-time 5% tax on the net worth of around 200 billionaires that live in the state. The windfall from this proposed tax would mostly go toward funding California’s healthcare programs. The state’s Medicaid program alone could lose up to $30 billion in federal funding once Trump’s budget cuts take effect next year.

Brin isn’t the only tech mogul seeking ways to avoid such a tax. It’s no coincidence that Meta founder Mark 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.

Prop 40 has also generated dissent from Governor Gavin Newsom (D-CA), who is concerned about the economic impact of these billionaires and their businesses fleeing California. Instead, Newsom has called for a “national billionaires’ tax.”

“Today, the office worker can shoulder a higher tax rate than the heiress,” Newsom noted in a blog post. “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.”

Californians will vote on Prop 40 in November. The organization that Brin is funding has proposed opposing ballot measures that, if passed, could effectively block Prop 40 by limiting the introduction of new taxes.

Meanwhile, Nvidia co-founder and unlikely working class hero Jensen Huang says he’s “perfectly fine” paying the tax.

“I have not even thought about it once,” Huang, who would owe around $8 billion in taxes, said in a January interview with Bloomberg. “We chose to live in Silicon Valley, and whatever taxes they would like to apply, so be it. I’m perfectly fine with it.”