California and Washington voters should look to Massachusetts before embracing higher taxes on wealthy residents, The Washington Post editorial board argued Sunday.

Massachusetts’ 2022 surtax on annual income above $1 million has raised billions for education and transportation, but the number of million-dollar-income tax filers fell 13.5% from 2021 to 2023, the Post said. The state also lost $4.2 billion in adjusted gross income to interstate migration in 2023.

The editorial cited research estimating billionaire departures have already removed about $570 billion from California’s proposed wealth-tax base, potentially undermining projected revenue from the measure.

Read more at The Washington Post.