- Colorado voters decide November third whether to replace the flat tax with six income-tax rates starting in tax year twenty twenty-seven.
- Supporters say about ninety-seven percent of taxpayers would get cuts, while higher rates would apply above five hundred thousand dollars.
- The measure faces a court challenge and rival cap; if both ballot measures pass, the one with more votes would control.
Colorado voters will decide Nov. 3 whether to replace the state’s flat 4.4% income tax with six rates beginning in tax year 2027. The proposal would cut taxes for most people with taxable income below $500,000 while raising rates above that level.
Supporters say about 97% of Colorado taxpayers would receive a cut. One estimate puts the maximum reduction for people below $500,000 at about $325 per taxpayer. Most cuts would be smaller.
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Chris deGruy Kennedy, president of the Bell Policy Center, said the campaign had gathered support from “more than 130,000 Coloradans” who are “tired of paying the same tax rate as millionaires.”
Supporters project about $2 billion in additional revenue annually for K-12 education, healthcare and childcare. A separate ballot-guide estimate puts the increase at about $2 billion in 2028, depending on economic conditions.
The measure’s supporters at Protect Colorado’s Future say the tax increases would fall only on the wealthiest 3% of individuals and the largest 5% of corporations making more than $500,000 annually. The campaign says the other 97% of taxpayers would get cuts.
Opponents describe the measure as a major tax increase and a structural rewrite of the state tax code. An editorial opposing it called the proposal “a $2 billion-a-year tax hike on the entire state” and said the top rate would nearly double.
The proposed rates rise above $500,000 in taxable income
The proposal sets six rates across taxable-income ranges:
| Taxable income range | Proposed rate |
|---|---|
| First $25,000 | 3.7% |
| $25,001 to $100,000 | 4.2% |
| $100,001 to $500,000 | 4.4% |
| $500,001 to $750,000 | 7.4% |
| $750,001 to $1 million | 7.9% |
| Above $1 million | 8.4% |
The first three rates stay at or below the current 4.4% rate. Higher rates begin on income above $500,000, with the top proposed rate applying above $1 million.
Estimates put the largest increases among a small share of taxpayers
An estimate says about 46,000 households, or about 1.36% of Colorado taxpayers, could see tax bills increase by an average of $26,000. People earning more than $1 million are considered most likely to pay more overall. That estimate describes a limited share of taxpayers.
The same analysis identifies about 340 filers with an average annual gross income of $280 million. They currently pay about $11.9 million in state income tax; the proposal would add about $10.8 million to their bill.
The campaign’s percentage claims and these estimates describe different measures of the effect. Supporters count taxpayers expected to receive a cut, while the household estimate identifies people projected to face higher bills.
A court challenge and rival tax cap frame the ballot fight
A lawsuit filed September 22, 2026, in Denver District Court seeks to remove the measure from the ballot. The defendants include Colorado Secretary of State Jena Griswold and proponents Chris deGruy Kennedy of the Bell Policy Center and Kiyana Newell of New Era Colorado.
The proposal is on the November 3, 2026, ballot and needs a simple majority to pass because it is not a separate constitutional tax-cap measure. It faces Proposition 136, which would cap the state income tax rate at 4.4%.
If both measures pass, the one receiving more votes would control their conflicting provisions.
