CA Billionaire Tax Act collect roughly $30B. Net Present Value: negative $39B

This analysis evaluates California’s 2026 Billionaire Tax Act, a one-time 5% levy on worldwide net worth above $1 billion, estimating revenue and behavioral responses using Forbes billionaire data, reports on residential holdings, and public departure announcements. Applying multiple methodologies, accounting for publicly confirmed out-migration that already removed about 30% of the taxable base, and applying a litigation-survival discount consistent with wealth-tax elasticity literature, the estimated revenue is roughly $30 billion (range $28-36 billion), far below a prior $100 billion projection. That revenue estimate is reported before fully accounting for reductions in other tax bases such as income tax.

The analysis also estimates that California billionaires pay $3.3-5.8 billion annually in state income taxes and computes the present value of permanently lost income-tax collections following departures. Those lost income-tax revenues more than offset the one-time wealth tax, producing a net present value of negative $38.9 billion. Across 100,000 simulated revenue and discount-rate scenarios, 85% of plausible outcomes yield a negative net present value for state revenues, indicating the policy is likely to reduce, rather than increase, long-term state tax receipts once behavioral responses and dynamic base effects are included.