Google co-founder Sergey Brin has now spent $100 million to fight the billionaire tax

Google co-founder Sergey Brin donated another $20 million to Build a Better California, bringing his spending against California’s proposed billionaire tax to more than $100 million. Prop 40 would impose a one-time 5% tax on roughly 200 billionaire residents, with proceeds largely funding healthcare programs as California faces potential federal Medicaid cuts.

The fight highlights how wealth taxes can trigger intense lobbying and relocation threats from ultra-rich tech founders. California’s debate may become a test case for whether states can tax billionaire wealth effectively, or whether pressure builds for a national approach instead.