> ## Content Index
> Fetch the complete content index at: https://www.westernslopetrellis.com/llms.txt
> Use this file to discover other available public pages before exploring further.

# Amendment 87 vs. Proposition 136: What Colorado’s Tax Measures Mean for Western Slope Residents
- URL: https://www.westernslopetrellis.com/amendment-87-vs-proposition-136-what-colorados-tax-measures-mean-for-western-slope-residents/
- Published: 2026-09-15T19:30:20.000Z
- Updated: 2026-09-15T19:30:20.000Z
- Description: Colorado voters face competing income tax measures this November. Amendment 87 would introduce graduated rates; Proposition 136 would cap rates at 4.4%. Here’s how they compare, what taxpayers could pay and why the outcome matters on the Western Slope.
- Author: Western Slope Trellis Staff
- Tags: Civic

Colorado taxes every dollar of taxable income at the same 4.4%, whether the filer reports $40,000 in Clifton or $4 million in Aspen. Two measures on the November ballot take opposite positions on whether that should continue.

[Amendment 87](https://www.coloradosos.gov/pubs/elections/Initiatives/titleBoard/filings/2025-2026/195Final.pdf?ref=westernslopetrellis.com) replaces the flat rate with six brackets starting in 2027\. [Proposition 136](https://www.coloradosos.gov/pubs/elections/Initiatives/titleBoard/filings/2025-2026/232FinalCorrected.pdf?ref=westernslopetrellis.com) caps the rate at 4.4% in state law. If both pass, [state law](https://colorado.public.law/statutes/crs%5F1-40-123?ref=westernslopetrellis.com) says the measure with more yes votes prevails wherever their provisions conflict.

This is the first in a series on the 14 statewide measures. Summaries of each are in the [voter guide](https://www.westernslopetrellis.com/2026-ballot-guide/).

## What Amendment 87 does to a tax return

The brackets work the way federal taxes do: each rate applies only to the income inside that bracket. The first $25,000 of taxable income is taxed at 3.7%, the next $75,000 at 4.2%, and everything from $100,000 to $500,000 stays at today’s 4.4%. Above $500,000 the rate rises to 7.4%, then 7.9% above $750,000 and 8.4% above $1 million.

For a taxpayer with $80,000 in taxable income, that is $3,235 in state tax instead of $3,520, a $285 cut before credits and other adjustments. At $150,000 the cut is $325\. That savings stays the same between $100,000 and $500,000 because the rate on income in that range does not change. A filer with $600,000 pays the higher rate only on the last $100,000 and owes about $2,675 more.

The same brackets apply to corporate taxable income. Profit from selling a primary home, above the federal exclusion, stays at 4.4%.

The rates themselves go into state statute, in the same sections that hold the current 4.4%. The constitutional change is narrower: it removes the sentence in TABOR that requires all taxable income to be taxed at one rate. Because that change only repeals language, the Title Board determined that Amendment 87 needs a simple majority, rather than the 55% required for amendments that add constitutional language.

The official ballot title puts the estimated additional annual revenue at $2.7 billion, after accounting for the lower-bracket tax cuts. That money goes into a new Colorado Future’s Account inside the general fund, restricted to K-12 education, health care and early childhood programs. It must supplement rather than replace existing spending. The TABOR exemption allows the state to keep that additional revenue rather than refund it.

## What Proposition 136 does

Proposition 136 writes a 4.4% ceiling on individual and corporate income tax rates into statute, beginning in 2027\. It does not cut anyone’s rate or change how the state spends what it collects.

If both measures pass and Proposition 136 receives more yes votes, Amendment 87’s upper brackets cannot take effect. The cap would also remain in state law beyond this election. TABOR already requires voter approval for any rate increase; a future proposal to raise the rate above 4.4% would also have to address the statutory cap.

## Who is behind each

Amendment 87’s supporting committees are [Protect Colorado’s Future Coalition and Yes for Colorado Kids](https://www.coloradosos.gov/pubs/elections/Initiatives/ballot/contacts/2026.html?ref=westernslopetrellis.com). The coalition includes the Colorado Fiscal Institute, Bell Policy Center and Western Colorado Alliance, the Grand Junction-based organizing group. The campaign says the measure cuts taxes for 97% of Colorado filers. That is a statewide estimate; we have not seen a Western Slope breakdown.

Seven committees are registered against it, including Americans for Prosperity Colorado and Keep Colorado Affordable.

Michael Fields and Suzanne Taheri, a former deputy secretary of state, are Proposition 136’s designated proponents. Its supporting committees are A Brighter Colorado and Keep Colorado Affordable.

Fields leads Advance Colorado, the sponsor of six of this year’s 13 initiatives. The group is organized as a 501(c)(4) nonprofit and does not publicly disclose its donors, which federal law does not require it to do. The ballot committees themselves file contribution reports with the Secretary of State. Those reports show which organizations, including Advance Colorado, are funding the campaigns.

## Why it matters here

Three Western Slope districts put mill levy overrides on this same ballot, and each names pay as the purpose: [D51](https://www.gjsentinel.com/news/western%5Fcolorado/d51-board-approves-ballot-language-for-23-2m-mill-levy-override/article%5F739efbf3-8c1f-4eea-8b87-0d63cdb9cf00.html?ref=westernslopetrellis.com) for staff raises and a teacher market adjustment, [Roaring Fork](https://www.rfschools.com/en-US/2026-mlo-mill-levy-override-e23b6c61?ref=westernslopetrellis.com) for teacher and staff pay and retention, and [Garfield Re-2](https://www.garfieldre2.net/?ref=westernslopetrellis.com) for staff salaries.

Those are property taxes, local and unaffected by the state measures. The statewide proposals concern income taxes: Amendment 87 lowers the tax calculated before credits for filers with positive taxable income up to $500,000, while Proposition 136 does not change the current rate. In the next installment, we’ll ask the districts whether additional state funding would change their plans.

Supporters of Amendment 87 describe the change as matching tax to ability to pay. Registered opponents, including Americans for Prosperity Colorado, describe it as a $2.7 billion tax increase. The Blue Book, due in mailboxes before ballots, will carry the Legislative Council’s arguments for and against both measures.

Mesa County [mails ballots Oct. 2](https://www.kjct8.com/2026/09/02/mesa-county-says-mail-in-ballot-process-unchanged-despite-new-usps-rule/?ref=westernslopetrellis.com). Both measures need a simple majority.

*Next in the series: Proposition NN and the three local school overrides.*