Three states have enacted new taxes on their wealthiest residents this spring, and a fourth is putting the question directly to voters. Washington Governor Bob Ferguson signed a 9.90% income tax on millionaires into law. Maine folded a high-earner surtax into its supplemental budget. Rhode Island moved forward with its own millionaire-level levy. And in California, organizers behind a first-of-its-kind billionaire tax say they have collected enough signatures to land on the November ballot.
Taken together, these actions represent the most concentrated burst of state-level wealth taxation in recent memory. They build on the momentum that began in 2022, when Massachusetts voters approved a 4% surtax on income above $1 million. That measure brought in roughly $2.2 billion in its first full year, according to the Massachusetts Department of Revenue. The lesson for advocates in other capitals was straightforward: tie higher taxes on the rich to schools, health care, and transit, and the public will back you.
Washington: a 9.90% rate with no general income tax to cushion it
Washington’s law is the boldest of the group and the furthest along. Governor Ferguson signed Senate Bill 6346 in spring 2026, creating what his office calls the Millionaires’ Tax. Starting in calendar year 2028, individuals earning more than $1 million will owe 9.90% on income above that threshold.
That rate is notably steeper than the Massachusetts model. It also lands in a state that has never had a broad-based income tax. Washington has long relied on sales and excise taxes, a structure that hits lower-income households hardest. Supporters framed the new levy as a correction to that imbalance.
“This is about asking the wealthiest among us to pay their fair share so we can invest in our kids, our health, and our future,” Governor Ferguson said in a statement when he signed the bill.
Revenue is earmarked for K-12 education, health care, and other state priorities. The legislation includes offsets designed to prevent increases in sales or property taxes. A separate effort to challenge the law through a voter referendum was rejected by the Washington Supreme Court, leaving the tax on firm legal footing. The bill’s fiscal analyses and committee testimony are available through the Senate Ways & Means Committee’s public schedule.
For Washington residents above the $1 million line, the 2028 start date opens a two-year planning window. Financial advisors in the state are already fielding questions about investment timing, charitable giving strategies, and whether relocating to a no-income-tax neighbor like Nevada or Wyoming makes financial sense.
Maine tucks a surtax inside a budget deal
Maine took a quieter path. Rather than passing a standalone tax bill, the legislature embedded new revenue from high earners inside a supplemental budget. The measure is LD 2212, tracked as HP 1491 in the 132nd Legislature’s records. Governor Janet Mills signed it on April 9, 2026.
“A bipartisan achievement that maintains core services while asking more from those at the top of the income scale,” Mills said in a statement from her office.
The precise rate and income threshold for the new surtax have not been detailed in any publicly available primary document as of June 2026. Implementing guidance from Maine Revenue Services is expected to fill in those specifics as the state moves toward the next fiscal year. Because the surtax is woven into a broader budget package rather than standing alone, it may be harder for opponents to isolate for a legal challenge. High-income Mainers should watch for that guidance to understand how the new layer interacts with the state’s existing graduated brackets and deductions.
Rhode Island: part of the wave, but details remain thin
Multiple news accounts have placed Rhode Island alongside Washington and Maine as part of the spring 2026 wave, reporting that the state adopted its own millionaire-level tax during the legislative session. However, as of June 2026, no signed bill text, specific bill number, governor’s press release, or official revenue projection from the Rhode Island Division of Taxation has surfaced in the public record.
That gap matters. Without primary documentation, the rate, income threshold, effective date, and projected revenue of Rhode Island’s reported levy cannot be independently verified. Taxpayers and policy watchers should treat this development as preliminary and look for official guidance from state authorities before drawing conclusions or making financial decisions based on it.
California’s billionaire tax: the biggest fight ahead
California’s effort goes further than any of the enacted laws in both ambition and the income level it targets. Proponents of a ballot initiative that would impose a new tax specifically on billionaires told the Associated Press that they gathered and submitted enough signatures to qualify the measure for the November ballot.
If enacted, it would be the first state-level tax explicitly aimed at billionaires. Revenue would be directed toward schools and social programs, according to backers. Opponents quoted in the AP report warned that the tax could drive wealth and investment out of a state where high earners already generate an outsized share of income tax revenue. The nonpartisan Legislative Analyst’s Office would typically prepare a fiscal analysis once the measure is officially certified.
One important caveat: ballot qualification in California requires the Secretary of State to verify the signature count. As of late May 2026, that certification had not been announced. The measure’s path to the November ballot is probable but not guaranteed. If it does qualify, expect one of the most expensive and closely watched state tax campaigns in years. Polling, campaign finance disclosures, and the Legislative Analyst’s fiscal summary will all shape the debate through Election Day.
The migration question that hangs over every state
Critics across all four states raise a familiar objection: taxing mobile wealth at the state level risks pushing high earners to relocate, hollowing out the very tax base the laws are designed to tap.
The evidence is real but more nuanced than either side typically acknowledges. A 2024 study from the Stanford Institute for Economic Policy Research found that millionaire migration in response to state taxes does occur but remains modest, with most high earners staying put even after rate increases. (The study has been widely cited in policy discussions, though readers seeking the full paper should search the institute’s publication archive for its 2024 work on millionaire mobility.) Opponents argue that the cumulative effect of multiple states raising rates at the same time could accelerate departures in ways that single-state research has not captured.
Supporters counter that the Massachusetts experience undercuts the flight narrative. The state’s millionaire surtax has now been in effect for more than two years, and revenue has met or exceeded projections without a measurable exodus of top earners. Whether that pattern holds as more states pile on remains an open question.
Revenue projections and legal challenges will shape the rest of 2026
After years of proposals that stalled in committee or lost at the ballot box, the millionaire tax movement is converting political energy into statute. Washington’s law is signed and scheduled. Maine’s surtax is embedded in a budget the governor has already approved. California’s billionaire tax is on the doorstep of the ballot. Rhode Island’s reported levy awaits confirmation.
No official fiscal projections for the Washington, Maine, or Rhode Island measures have been published as of June 2026. Readers should watch for formal revenue estimates from each state’s budget or revenue agency as implementation approaches. The numbers that emerge will determine whether 2026 is remembered as the year the millionaire tax went mainstream or as a peak that triggered the backlash its opponents have long predicted.
