November 2025 marks the three-year anniversary of Massachusetts voters approving a 4 percent surtax on annual incomes above $1 million. What this means is that if you live in Massachusetts, you pay 5 percent of your annual income up to $1 million. If you make any more than that, you pay 9 percent on income above a $1 million. This is in addition to the state sales tax and local property taxes, which you pay directly as a homeowner or indirectly as a renter.

The “Fair Share” amendment has been a reference for New York City mayor-elect Zohran Mamdani, who has called for an additional 2 percent tax on city incomes over $1 million to fund his affordability agenda. Predictably, critics make gloomy prophecies of economic blight and elite exodus: Bill Ackman and twenty-six other billionaires spent big on Mamdani’s opponents, the Cato Institute called his tax plans “wishful thinking,” and Andrew Cuomo threatened to depart for Florida.

Massachusetts voters heard the same arguments in 2022. Spearheaded by Patriots owner Robert Kraft, New Balance’s Jim Davis, and Boston investment firm CrossHarbor Capital Partners, the opposition argued that Fair Share would not address the state’s fiscal needs; it would create tax flight and punish homeowners selling on the market. Three years on, what are the effects of the millionaire tax? The evidence is that Fair Share revenue has exceeded expectations: it’s repaired bridges, funded bus routes, hired teachers, and made community college and school meals available to all. There has been no significant outmigration of the wealthy. In fact, the number of millionaires by net worth has increased by over 30 percent, and the outward tide of nonrich, young workers has slowed.