2026 Voter Guide: This article is part of Johnstown Republic’s guide to the Nov. 3 ballot.
Colorado voters will decide Proposition 136, a citizen-initiated measure that would set 4.4% as the maximum state income-tax rate for both individual and corporate taxpayers beginning in 2027.
The measure would not change the current tax rate. Instead, it would place the existing 4.4% rate into state law as the maximum allowed rate. Proposition 136 requires a simple majority to pass, according to the official 2026 Colorado Blue Book.
What would Proposition 136 do?
Colorado currently taxes individual and corporate income at 4.4% of taxable income.
Proposition 136 would keep that rate in place and establish it as the maximum rate allowed under state law beginning Jan. 1, 2027.
The measure would not prevent future tax-rate reductions. The General Assembly or voters through a citizen initiative could still lower the income-tax rate.
Colorado’s Constitution already requires voter approval before a tax rate can be increased. Proposition 136 would add a statutory 4.4% ceiling on top of that existing requirement.
What does a YES vote mean?
A YES vote would establish the current 4.4% state income-tax rate as the maximum rate for individuals and corporations.
The current rate would remain unchanged unless it is later reduced.
What does a NO vote mean?
A NO vote would leave current law in place.
The state income-tax rate would remain 4.4%, but that rate would not be established as a separate statutory maximum. Any future tax-rate increase would still require voter approval under the Colorado Constitution.
What would it cost?
Proposition 136 is expected to have no immediate fiscal impact because it does not change the current tax rate.
The Legislative Council Staff fiscal analysis estimates no change in state or local government revenue or spending as a direct result of the measure.
Arguments for and against
Supporters argue that Proposition 136 would reinforce the current 4.4% income-tax rate and prevent future lawmakers from adopting a higher rate without first addressing the statutory limit. They also argue that maintaining the current rate helps keep Colorado’s income taxes comparatively low.
Opponents argue that the measure would add little practical protection because Colorado already requires voter approval for tax-rate increases. They also argue that Proposition 136 could create legal uncertainty if Amendment 87 also passes because the two measures contain conflicting income-tax provisions.
What if Amendment 87 also passes?
Colorado voters will also consider Amendment 87, which would replace the flat income tax with graduated rates.
Under Amendment 87, income above $500,000 would be taxed at rates higher than 4.4%, directly conflicting with the cap proposed by Proposition 136.
The Blue Book says that when voter-approved measures conflict, the outcome is generally determined by which measure receives more votes. However, if both Amendment 87 and Proposition 136 pass, the state says the exact outcome is unclear and could ultimately be resolved by the General Assembly or a court.
What does this mean for Johnstown?
Proposition 136 would apply statewide, including to individual taxpayers and businesses in Johnstown.
Because the measure would not change the current 4.4% tax rate, there would be no immediate change in income-tax bills solely from Proposition 136.
Its significance would primarily involve whether future income-tax rates could exceed 4.4%, particularly if Amendment 87 also passes.
Official information
The complete ballot analysis, fiscal-impact statement and full text of Proposition 136 are available on the Colorado General Assembly’s official Proposition 136 page.