Meet the California multimillionaires demanding the billionaire tax become law

California's Proposition 63 would impose a 13% tax on assets exceeding $2 million for a single filer—affecting roughly 6,200 of the state's wealthiest residents. The measure hits the ballot this November after years of failed attempts. The open letter, signed by wealthy Californians including venture capitalists, tech entrepreneurs, and entertainment figures, landed as the campaign enters its most expensive phase: the state's Legislative Analyst's Office projects the tax could generate $8 billion annually by 2028, assuming the state survives the inevitable legal challenges. This isn't the state's first swing at a wealth tax. Washington attempted one in 2022 and faced immediate constitutional litigation. Illinois tried and repealed its version in 2015 after implementation proved administratively nightmarish. What makes Prop 63 different: its backers are building a narrative that the tax is pro-growth, not punitive—framing it as a fairness correction in a state where income inequality has widened 40 percent in the past decade.

The signatories include names like venture capitalist Chris Sacca and Silicon Valley investors who've calculated, correctly, that $2 million thresholds catch far more wealthy professionals and successful entrepreneurs than true billionaires. This creates the cover they need: they're not threatening themselves, just the ultra-wealthy tier above them. But the mechanism matters. The tax applies annually to asset values, not income or capital gains. That means someone with a $3 million house, a $1 million investment portfolio, and a modest business could owe $13,000 per year in tax on assets they may not be liquidating. Enforcement requires annual valuations of private businesses, private real estate, and illiquid holdings—something that doesn't exist at California's tax authority.

Conservatives see this straightforwardly: it's politicians and a complicit subset of the wealthy using envy as policy. The argument isn't wrong that billionaires pay less as a percentage than middle-class earners—but the solution being proposed is a tax that's never worked elsewhere, targets people who earn nothing from their assets in bad years, and has already prompted warnings from financial advisors that it will accelerate California's population flight. Real estate brokers report wealthy families already pricing out scenarios where the tax passes. The state is already hemorrhaging top earners to Texas, Florida, and Nevada; a wealth tax on assets, not income, is a compounding pressure that doesn't require a crash to trigger—just an ordinary market correction. Why demand your accountant track a $500,000 wine collection annually, or face underpayment penalties?

What's genuinely at stake: if Prop 63 passes and survives its certain court challenge, it becomes the template for other states and potentially federal legislation. Massachusetts attempted a wealth tax twice recently; New York's considering it. The legal questions are immense—the Sixteenth Amendment taxed income specifically, and courts have repeatedly held that wealth taxes require workarounds or constitutional changes. But the political momentum matters more than the constitutional obstacles right now. If Californians vote yes, it signals that even affluent voters view the status quo as unsustainable.

Watch for the November vote itself, then the immediate lawsuits. Attorneys general in other states, particularly Republican ones, are already preparing challenges on dormancy grounds—whether California can tax wealth held in other states. The Proposition 13-era Supreme Court's recent decisions on property tax suggest skepticism toward novel tax mechanisms, but wealth tax litigation hasn't reached the Court yet. If Prop 63 passes by more than 60 percent, expect federal wealth tax proposals to materialize within two years. If it fails, expect backers to argue they didn't spend enough on messaging—and return in 2026.