Proposition 136: Income Tax Rate Limit

What It Would Do

Proposition 136 would write into state statute (not the constitution) that Colorado's individual and corporate income tax rate cannot exceed the current 4.4%, effective January 1, 2027. On its own, it would not change today's tax rate — Colorado's rate is already 4.4% — but it would block the graduated-rate structure proposed by Amendment 87, also on this ballot, which raises rates as high as 8.4% on income above $1 million. If both measures pass, resolving the conflict between them would likely fall to the legislature or the courts.

Fiscal Impact

Per the state's official Blue Book analysis: "The measure limits the state income tax rate to no higher than the current rate of 4.4 percent. This results in no change to state or local government revenue or spending. For this reason, the measure has no fiscal impact." That's because it locks in the existing rate rather than changing it — but it would prevent the graduated-tax revenue proposed by Amendment 87 from ever taking effect if both measures pass.

Why We're Voting No

Boulder Progressives opposes Proposition 136 because it would permanently lock in a flat tax rate regardless of future needs, undercutting funding for schools, health care, and other priorities, and stands in direct conflict with the fairer graduated-rate approach in Amendment 87.

Sources: 2026 Colorado State Ballot Information Booklet (Blue Book), Legislative Council Staff.