The top 1% of Americans now hold over 31% of national wealth — roughly $55 trillion in net worth. A recent NBER paper found the richest 384 Americans paid an effective rate of just 24% on economic income in 2025, versus 30% for the average taxpayer. ProPublica's reporting confirmed that billionaires like Musk, Bezos, Buffett, and Bloomberg live largely tax-free by minimizing realized income and hoarding unrealized gains until death. This is the structural backdrop against which California launched its experiment. Proposition 40, on California's November ballot, would impose a one-time 5% tax on the wealth of billionaires who resided in the state on January 1, 2026. The state had 260 billionaires holding nearly $2.5 trillion at the time. Six Nobel laureates endorsed the measure, calling it 'the first-ever tax on billionaire wealth enacted anywhere in the world.' Optimistic projections put the revenue at $110 billion, earmarked largely to replace Medicaid funding gutted by Trump's One Big Beautiful Bill Act. The opposition mobilized immediately and massively. Google co-founder Sergey Brin coordinated roughly $200 million to fight Prop 40 and promote two counter-propositions — Props 41 and 42 — designed to bar retroactive taxes and forbid new taxes on financial assets. Brin and Larry Page moved business interests out of California before the January 1 deadline. Travis Kalanick decamped to Texas. Peter Thiel relocated to Miami. The fast money tried to outrun the tax date. The sneaky calendar maneuver — springing the initiative in late November 2025 with a January 1 effective date — was deliberate. The Nobel economists argued the window was too short for significant flight. And indeed, between January and October 2026, California's billionaire count actually grew by 20. New York, despite a combined top rate exceeding 14.8%, still hosts 154 billionaires; nine of the ten richest live in New York City. Billionaires are sticky, embedded in social and business networks that resist relocation. But the longer-term behavioral evidence is less reassuring. After George W. Bush's 2001 tax changes eliminated the federal credit offsetting state estate taxes, over a fifth of Forbes 400 billionaires in estate-tax states moved to non-estate-tax states by 2010. Forbes 400 wealth subject to state estate taxes dropped from $203 billion to $122 billion between 2001 and 2017. Moretti and Wilson's research shows the ultra-rich are highly sensitive to estate tax differentials — and a 5% one-time wealth levy is a far larger shock than an estate tax gap. Stanford economists concluded that Prop 40 would raise only about $30 billion rather than $110 billion, while triggering income tax revenue losses with a net present value of nearly $39 billion — making the measure a net fiscal negative. Swiss canton-level wealth tax studies corroborate the pattern. A September poll showed Prop 40 falling just short of majority approval. Even if passed, it faces constitutional challenges on retroactive taxation and due process grounds. Some assets like real estate would be excluded; foreign billionaires may shelter under double taxation treaties. The deeper problem transcends California. Democratic governance requires the ability to tax the economic winners who benefit most from the state's infrastructure, legal systems, and social stability. But wealth at this scale is mobile, and the competition among jurisdictions creates a race to the bottom. Governor Newsom and his would-be successor Xavier Becerra oppose the measure — not on principle but on pragmatics. The survival question isn't whether billionaires should be taxed, but whether any sub-national jurisdiction can do it alone without triggering the very capital flight that makes the exercise self-defeating.
