“I am so excited to say the voters of Colorado heard our case and supported us,” said Kathy White, executive director of the Colorado Fiscal Institute and a steering committee member of Protect Colorado’s Future, the coalition of education, health care, child care and other groups that gathered hundreds of thousands of signatures to place the measure on the ballot.

Amendment 87 would amend the Taxpayer’s Bill of Rights, or TABOR, to replace Colorado’s flat income tax with a tiered system. The rate would drop for the lowest earners and rise for the wealthiest. The dividing line between households and businesses that would pay more versus less is roughly $500,000 a year, though some estimates put it as high as $1 million depending on the filer. Backers expect the change to generate about $2.7 billion annually for K-12 schools, health care and child care.

“I think the message is that voters have made the choice to make a huge change in the direction of our state, making investments in regular working people,” said Chris deGruy Kennedy, president and CEO of the Bell Policy Center, a former Democratic lawmaker and co-chair of Protect Colorado’s Future. “Regular folks are going to get a tax cut, and then we’re going to see a huge new investment in K-12 education, healthcare, and childcare that’s going to pay huge dividends for regular working people and older adults.”

The measure split Democrats and drew high-profile opposition from incoming Gov. Phil Weiser, the state attorney general, and outgoing Gov. Jared Polis, along with former U.S. Sen. Ken Salazar. Polis warned this week that doubling the rate for small and medium-sized businesses would lead to “massive unemployment” and drive companies from Colorado. “I’m fine with what it does with individual taxes,” he said. “What I’ve talked about is what it does and doubling the rate for small businesses and medium-sized businesses.”

The Colorado Chamber, which spent financial, legal and messaging resources against the measure, said Friday it was “incredibly disappointed” by the outcome. “Small business owners work their entire lives to achieve the American dream, but this measure will penalize them for achieving that dream,” CEO Loren Furman said in a statement. “These tax increases will force businesses to make difficult decisions about wages, hiring and future investments.”

The apparent passage comes amid a deep state budget crisis. Earlier this week, Polis proposed $600 million in cuts to projected Medicaid spending in his final budget. Supporters say the new revenue could soften those reductions. “I think we’ll be able to spare some of the pain,” said Rep. Lorena Garcia, an Adams County Democrat on the House Finance Committee. “We will be able to give people back their healthcare. We’ll be able to help close the childcare wait list. We’ll be able to give more funding to schools so that they’re not having to lay off their teachers.”

Nicole Villas, a Gilpin County mother of an adult son with severe epilepsy who relies on Medicaid, said she signed the petition to put Amendment 87 on the ballot and voted for it. “It has been a long time since I’ve woken up without fear of what will have to be cut next,” she said, noting that the governor’s proposed 2027-28 budget eliminates adult dental coverage for Medicaid enrollees. “Amendment 87’s passing gives me hope that Medicaid will be able to continue to fund Members’ basic needs and keep them supported in the community where they belong.”

The measure’s path to the ballot was contentious. Opponents sued over signature-gathering practices, arguing the Secretary of State’s office should have invalidated signatures collected by paid circulators. A district court dismissed the challenge on Oct. 21, and the Colorado Supreme Court upheld the measure five days before Election Day. A competing proposal, Proposition 136, which would have capped the state income tax at 4.4%, appeared on track to fail.

The state Department of Revenue said its taxation division is already preparing for the change, updating income tax and withholding forms and processing systems for the 2027 tax year, which will be filed in 2028. Draft versions of the Colorado Withholding Worksheet for Employers have been released, and the final version is expected in the coming weeks. The agency is also updating the Colorado Employee Withholding Certificate. “The beginning of the tax year is a good time to review your withholding,” said Leonardo Torréss, the department’s business and multicultural marketing and communications manager.

For supporters like Arianna Morales, deputy director of the youth civic advocacy group New Era Colorado, the win reflects a generational shift. Carrying a sign reading “A Tax Code That Works For Everyone” and wearing a hat that said “I like to make billionaires cry,” she said, “The biggest thing we heard while talking to young people is they think it’s time to tax the rich their fair share.”