Silicon Valley is going to war with Sacramento. Tech tycoon Peter Thiel has fired the opening salvo in what promises to be the most expensive ballot measure fight in history, donating $3 million to a committee dedicated to crushing California’s proposed "Billionaire Tax."

The disclosure, filed on Friday, reveals that Thiel is the primary backer of the California Business Roundtable's campaign against the initiative. The proposed law would impose a tax on "unrealized capital gains"—meaning the wealthy would pay taxes on the increase in value of their stocks and property, even if they haven't sold them.

The "Exit Tax" Panic

For tech founders like Thiel, whose wealth is tied up in company stock, this is an existential threat. "It is a confiscatory tax on innovation," argued a spokesperson for the opposition group. They claim the tax would trigger a mass exodus of startups to Texas and Florida, hollowing out the state’s economy.

• The War Chest: Thiel’s donation is just the beginning. Insiders estimate that Silicon Valley and Hollywood moguls will raise over $75 million to defeat the measure. They view it as a slippery slope toward socialism.
• The Proponent's Argument: Supporters, including unions and progressive Democrats, argue that the ultra-rich pay a lower effective tax rate than teachers or firefighters because they live off loans against their stock. The revenue is earmarked for schools and homelessness services.
• The Thiel Factor: Peter Thiel, a libertarian firebrand who backed JD Vance and Donald Trump, is a polarizing figure. His involvement nationalizes the issue, turning a state tax dispute into a proxy war between the populist right and the progressive left.

A Referendum on Wealth

If the measure makes it to the November ballot, it will be a test of California’s appetite for redistribution. Thiel is betting $3 million that even in the bluest state in America, voters still aspire to be billionaires, not tax them out of existence.