Gianforte Launches Flat Income Tax Initiative

Gov. Greg Gianforte announced his support for a public education campaign supporting a flat 4.7% state income tax at a press conference in the Capitol Tuesday, arguing that a flat rate — which would reduce the higher of the state’s two rates — would boost the state’s economy. 

“Montanans know how to spend their money better than the government does,” Gianforte said.

Gianforte stood at a podium in the rotunda alongside Jack Baum, a state affairs manager with Washington, D.C.-based nonprofit Americans for Tax Reform, and Chris Cargill, president of Mountain States Policy Center, an Idaho-based free-market think tank that was recently in Montana to promote redrafting Montana’s Constitution. Mountain States Policy Center is organizing the “Flat. Fair. Montana.” campaign.

Gianforte, who has prioritized decreasing income taxes during his five-and-a-half-year tenure in the governor’s office, said in February 2026 that he wanted the 2027 Legislature to send a flat-tax bill to his desk. Gianforte told Montana Free Press after the press conference Tuesday that the proposal is “one of our top priorities.” His team hasn’t drafted legislation, he said, but “the language is simple.”

“The lawyers will probably make it long, but in my mind, it’s one line. Everybody pays the same rate: 4.7%,” Gianforte told MTFP.

In July, a handful of Republicans in Senate leadership announced their support for a flat tax. And Speaker of the House Rep. Brandon Ler, R-Savage, said in a statement Tuesday that he supports the proposal and that “House Republicans are ready to get it done.”

When Gianforte took office in 2021, the top Montana rate of seven income tax brackets was 6.9%. Gianforte has decreased the number of brackets to two, and in 2025 signed a bill that scheduled the top bracket, then at 5.9%, to decrease to 5.4% by 2027. 

If the flat-tax proposal succeeds, it would not directly affect people in Montana’s current lower bracket — for instance, a single person making less than $65,000 in taxable income annually in 2027 — because their rate is already 4.7%. 

The state budget is significantly reliant on income and property taxes because Montana is one of five states in the nation without a statewide sales tax.

Eight states, including Montana neighbors South Dakota and Wyoming, have no state income tax, according to a Tax Foundation report from 2025. Fifteen, including neighboring Idaho, have a flat income tax. 

Montana’s Legislative Fiscal Division estimated in July that a 4.7% flat tax beginning in 2028 would reduce state revenues by $140 million over the 2029 biennium.

Rose Bender, director of research for the Montana Budget and Policy Center, a nonprofit that has been critical of Gianforte’s tax policies in the past, denounced Gianforte’s proposal Tuesday. 

“The Governor’s push to further cut Montana’s top income tax rate will result in a significant tax cut to the wealthiest 5 percent, the same individuals already benefiting from past tax breaks,” Bender wrote in a statement.

The proposal also drew criticism from two Democratic lawmakers who focus on tax policy, Rep. Mark Thane, D-Missoula, and Sen. Dave Fern, D-Whitefish.

In a written statement co-published with Fern, Thane called Gianforte’s pitch a “tax break for the wealthiest income earners.” 

“If there’s one thing we have learned, it’s that trickle down economics is a myth,” Thane wrote.

“Businesses and working families expect and deserve a quality public school system, well-funded public safety, affordable housing projects, and workforce development. All of that is threatened by the flat tax,” Fern wrote in the same release. 

At the press conference Tuesday, Gianforte preemptively rebuffed critics’ argument that a flat tax would “harm the budget,” suggesting that lower income taxes promote economic growth and ultimately increase state coffers.

“Let’s admit it, there’s just no way to tax your way to prosperity. Only lower taxes and common sense budgeting can do that,” Gianforte said. 

The press conference was well attended by small-government advocates including representatives of the Frontier Institute, a Helena-based free-market think tank, and Americans for Prosperity-Montana. Americans for Prosperity’s funders include the Koch family and members of the Walton clan, owners of Walmart.

“AFP-Montana is going to be fully behind the flat tax,” Henry Kriegel, the organization’s deputy state director, told MTFP after the press conference. “We anticipate unleashing our grassroots army around the state to get behind it.”

After the press conference, Gianforte said he is proud to have “significantly reduced property taxes for Montanans.”

“But to finish the job, we need to get the flat tax on income,” Gianforte said. 

This story originally appeared in the Montana Free Press, which can be found online at montanafreepress.org.