Google cofounder Sergey Brin has made his largest single public donation yet to address California’s housing crisis, just weeks after making a $42 million mansion on the Nevada side of Lake Tahoe his primary residence, according to new filings and property records. The move illustrates how one of the world’s richest men is trying to shape the future of a state he is increasingly distancing himself from physically and, potentially, for tax purposes, as questions swirl over how many California billionaires might leave the state with a ballot initiative in the balance, targeting 1% of their wealth.

Brin has committed $20 million to a new organization called Building a Better California, a political and policy effort aimed squarely at California’s worsening housing affordability problems, recent state disclosures show, as first reported by the New York Times. The money is part of a broader $35 million launch package that includes $15 million from eight other wealthy business leaders, among them former Google CEO Eric Schmidt and venture capitalist Michael Moritz, who each contributed $2 million. Roughly a week earlier, another Silicon Valley billionaire, Peter Thiel, made his largest political donation in years, contributing $3 million to a California business group leading the fight against a proposed billionaire wealth tax.