Nine Tax Measures Hit State Ballots This Year—Six Times the Usual Pace

Voters in six states will decide nine statewide income or wealth tax measures this midterm season — a sharp break from the historical pace of roughly one and a half per year. From 2000 to 2025, according to Ballotpedia, voters decided just 40 such measures, splitting evenly: 20 approved, 20 defeated.

California's Prop 40 has grabbed the headlines — and the billionaire money fighting it. The measure would impose a one-time 5% levy on net worth to help offset federal cuts to health spending. Opponents, including billionaires, have poured tens of millions into defeating it. Google cofounder Sergey Brin and others back Props 41 and 42, which would effectively kill Prop 40 if it passes.

Where did all these measures come from?

Not from lawmakers, mostly. Citizen initiatives created by activists and unions account for most measures that would create or raise taxes on the rich. This year, tax-the-rich measures appear in California, Colorado, Washington, Massachusetts and Cook County, Illinois.

The politics cut across party lines. California Gov. Gavin Newsom and Democratic gubernatorial candidate Xavier Becerra both oppose Prop 40, while the California Democratic Party endorsed it — and Newsom has since backed Prop 42. In Colorado, Democratic Gov. Jared Polis opposes the graduated income tax amendment. In Washington, Democratic Gov. Bob Ferguson leads the defense of the state's new tax.

These states carry serious corporate weight. California holds 56 Fortune 500 headquarters, Illinois 29, Massachusetts 15, Washington nine and Colorado seven. Per Forbes's 2023 count, California counted 186 billionaires, Illinois 23, Massachusetts 22, Washington 13 and Colorado 12.

Republican-leaning states are moving the other way, with three measures to constrain taxes:

• North Carolina would cut its constitutional income tax cap in half, to 3.5%
• Iowa would require a two-thirds legislative vote to raise income taxes
• Utah would require 60% voter approval for new or higher taxes

Missouri's Republican-led Senate sent voters a plan to invest state money in the S&P 500 until the returns can replace taxes. "Over the last few years, we've seen a divergence in state income taxes and taxes on high earners," Jared Walczak of the Tax Foundation told CNBC.

What's happening in Washington?

Washington voters rejected income taxes in 10 ballot measures between 1934 and 2010. The 2010 fight split the state's richest families: Steve Ballmer and Jeff Bezos each gave $100,000 to oppose it; Bill Gates Sr. gave $500,000 to support it. This year, lawmakers passed a millionaires tax themselves after a 25-hour floor debate, and opponents have countered with a repeal measure.

Amazon, Microsoft and Costco are all headquartered in Washington. Bezos has already sold his Seattle mansion and moved to Miami; Ballmer, Gates and MacKenzie Scott remain. If the tax survives, it takes effect in 2028, with first payments due in April 2029.

How did Colorado and Massachusetts get here?

Colorado's Amendment 87 would replace the 4.4% flat tax with six brackets, from 3.7% up to 8.4% on income over $1 million. Colorado would become the third state ever to switch from a flat to a progressive income tax — over its own Democratic governor's objection.

Massachusetts, the second state to switch, has seen surtax revenue exceed projections, bringing in more than $3 billion in the 2025-2026 fiscal year. Voters will now decide whether those proceeds count toward the state's revenue limit.

What does the Cook County vote actually do?

Nothing, legally. The question is advisory. Illinois House Speaker Emanuel "Chris" Welch dropped a statewide millionaires tax this year when Democrats couldn't muster the supermajority to put it on the ballot. The state's 2020 attempt failed 55% to 45% after Gov. JB Pritzker spent $56 million supporting it and Citadel's Ken Griffin spent nearly $54 million opposing it. An advisory vote in the county that includes Chicago lets supporters test the waters without risking another statewide loss.

One footnote: Pritzker is running for reelection, and his race drew Pope Leo XIV, the Chicago-born pontiff, who became the first pope to vote in a U.S. election. "If the Pope can vote all the way from Vatican City, you can too!" Pritzker posted. The pope votes in Will County, though, so the Cook County question isn't on his ballot.

November's results will show whether the post-2025 wave of tax-the-rich campaigns is peaking or just getting started.