What if it passes?
The interactive below models the two largest open variables: how many billionaires leave, and how their wealth is composed. Every number is calculated from the published papers, with the inputs and formulas exposed below the result. Move the controls. Read the math. Decide for yourself.
Share of California billionaire wealth that exits the tax base before January 1, 2026 (or successfully avoids taxation post hoc). The single most disputed number in the literature.
Of the $1.899T California-resident billionaire base on Jan 1, 2026, the migration response moves a slice out before the rate applies. The 5% rate hits only what remains.
Green spike at Y1: one-time wealth tax revenue. Red drag downward every year: ongoing income-tax loss from departed billionaires. Gold line: cumulative net position. Where it crosses zero is when the ongoing loss has consumed the one-time gain.
Annual appropriation caps are set by §16355(c). Total revenue divided by the cap gives the minimum number of years it would take to draw down the Reserve Fund: ~2.7 years for the Health Account at the cap rate.
∑(remaining wealth × 5%) × apportionmentMigration removes wealth from the base before the 5% rate is applied. Only the wealth that remains in California-resident hands on January 1, 2026 is taxed.
∑ (departing wealth × fiscal-income ratio × CA effective rate × jurisdictional share)Fiscal-income ratios from BSYZ NBER 34170: 1.75% top-100, 3.46% next-300. Effective rates blend federal investment-income (23.8%) and CA top-bracket (~12.3%). Jurisdictional share assumes future income gets sourced to the new state of residence.
captured implicitly in the $3.53B–$4.49B headlineWalczak rolls consumption-tax effects into the headline range without breaking them out separately. The bulk of the loss is from individual income tax.
annual loss ÷ 39M Californians$3.53B ÷ 39M ≈ $90/yr. $4.49B ÷ 39M ≈ $115/yr. Read as: if Walczak is right, every Californian pays for ongoing services that were previously funded by departed billionaires.
Not a prediction. A model.
All scenarios shown are derived from the cited research papers with their stated assumptions. The migration-response slider is the most contested variable in the literature. The proponent and opposition camps disagree by a factor of five or more on this single number. The simulator lets you sit in either camp and see what each implies.
Built by @davidtphung. NLT143 / Matter Vertical.