State’s voters will decide between competing income tax ballot measures, likely without realizing all the implications
The Nov. 3 Colorado ballot includes two directly competing state income-tax measures. Freda Miklin reports how Amendment 87 and Proposition 136 interact if both pass.
Freda Miklin ·
In recent years, sponsors of Colorado ballot measures have become increasingly effective at gathering enough signatures to qualify their proposals for the ballot. This year, they went 14 for 14: every measure approved for circulation received enough valid signatures to appear on the November 3 general election ballot.
It is also becoming increasingly common for citizen-initiated ballot measures in Colorado to give rise to related ballot measures that compete with or even cancel out the original one.
The November 3 ballot—scheduled to begin arriving in Colorado voters’ mailboxes on October 2—will include two directly competing state income tax measures. Given the complexity, many voters may not fully understand how their votes on both measures could interact.
Amendment 87, “Graduated Income Tax,” is a seven-page proposal combining statutory changes with a constitutional amendment. It would slightly reduce state income taxes for taxpayers with federal adjusted gross income (AGI) of $100,000 or less, while significantly increasing taxes on Colorado’s highest-earning individuals and corporations.
We calculated that, under Amendment 87, taxpayers with AGI of $60,000 would save $245, or 9% compared to what they currently pay, annually. Taxpayers whose AGI is $750,000 would pay $7,175 more per year, a 22% increase over the current flat tax. Those with AGI of $1,500,000 would pay $35,925 more, or 54% above what they pay now. The percentage increase rises from there.
If enacted, Amendment 87 is projected to raise $2 billion to $2.7 billion annually, depending on the estimate. That revenue would be exempt from TABOR limits and earmarked for “K-12 public school education, health care, early child care, and education programs,” providing a substantial boost to the state’s current $46.8 billion budget. Some of the ways that that additional money could be used are not specific, a concern to non-supporters.
Proposition 136, “Income Tax Rate Cap,” is a one-sentence statutory change that would cap state income taxes for individuals and corporations at the current 4.4% rate for 2027 and future years.
Because the two measures directly conflict, voters likely want to know what happens if both pass. The answer is complicated—and illustrates the challenges that can arise when laws or constitutional changes are made through petition-driven initiatives rather than the elected state legislature, where proposals are subject to committee review, testimony, and vigorous public debate, during which they are fully vetted.
According to an analysis by Common Sense Institute, if both Amendment 87 and Proposition 136 receive more yes votes than no votes, statewide, on November 3, “The future of Colorado’s income tax system will be decided by which initiative garners more ‘yes’ votes. Should Proposition 136 have a higher ‘yes’ vote total, not only will the top tax rate remain at 4.4%, but the tax cuts proposed by Amendment 87 on earners making $100,000 or less would also take effect. On net, Colorado taxpayers would see an income tax reduction. Should Amendment 87 get more ‘yes’ votes, the graduated income tax structure will pass in full.”
The Villager researched the history of Colorado’s state income tax rates.
From 1937 to 1987, Colorado used a graduated income tax system in which higher earners paid higher state income tax rates. That changed in 1987 when lawmakers adopted a single, flat rate of 5%.
In 1992, Coloradans passed the Taxpayer Bill of Rights (TABOR), a ballot measure crafted by Douglas Bruce, a colorful character who was later elected El Paso County Commissioner and appointed to the state legislature, before eventually being convicted of four felonies, including money laundering, attempted bribery of a public official, and tax fraud involving the use of a charitable organization. But we digress.
TABOR required Colorado to maintain a flat income tax, though it did not set the rate. Following the initial 5% rate, lawmakers lowered it to 4.75% in 1999 and again to 4.63% in 2000.
In 2020, voters approved a ballot initiative lowering the rate to 4.55%. Proponents returned in 2022 with another ballot initiative that voters adopted, lowering the rate again, this time to 4.4%, where it has remained through 2026.
In February 2020, the Bell Policy Center (Bell), a local non-profit, non-partisan, progressive research and advocacy organization, began advocating for a return to a graduated income tax, arguing it would be less regressive and fairer than the flat tax.
That effort culminated in September 2025, when Bell, together with the Protect Colorado’s Future coalition, filed Ballot Measure 195, now Amendment 87, which would significantly increase state income taxes on individuals and corporations with federal taxable income above $500,000, lower taxes for those making under $100,000, and leave rates unchanged for Coloradans with AGI between $100,000 and $500,000.
Supporters of a graduated income tax argue that higher earners should pay a larger share of their income in taxes and that the added revenue would help fund the areas named in the proposal: public K-12 education, health care, child care, and education programs.
Opponents argue that the new TABOR-exempt revenue would encourage unnecessary spending, and that Colorado’s low, simple, flat tax helps attract and retain businesses to our state that support the state economy. They also contend that Colorado has become less attractive to new businesses and residents in recent years, and they warn that because the income thresholds are not tied to inflation, higher rates could affect more taxpayers over time.
Proposition 136 was certified for the ballot on August 20. Amendment 87 was certified on September 1.
When Amendment 87 was certified, Bell posted on X: “Income Tax Fairness is on the ballot! Colorado’s tax system is broken. A nurse or teacher making $50K pays the same rate as a millionaire or big corporation. Under Initiative 195 (now Amendment 87), 97% of taxpayers get a tax cut, & no one under $500K pays a penny more.”
Michael Fields of Advance Colorado, the designated representative for Proposition 136, responded, “Voters aren’t going to support a measure that raises taxes on seniors, veterans, and small businesses.”
Print source: The Villager, Vol. 44 No. 42, Sept. 10, 2026, page 6. Issuu edition.