Colorado Taxes on RSUs and Stock Options: A Tech Employee's Guide

Colorado has emerged as a legitimate tech hub. Palantir relocated its headquarters to Denver in 2020. Google runs a major engineering office in Boulder. Arrow Electronics, Ibotta, Gusto, and a deep bench of Techstars-backed startups call the Front Range home. For tech employees who live in Colorado or are considering a move there, understanding how the state taxes equity compensation is essential.

The headline is straightforward: Colorado levies a flat 4.4% income tax on all income — no brackets, no phaseouts, no special rate for long-term capital gains. That's meaningfully cheaper than California (up to 13.3%) and New York (up to 13.5% combined with NYC), and applies uniformly to RSU vests, salary, bonuses, and capital gains alike.

The less-known detail: Colorado has a state alternative minimum tax at 3.47% — a real cost for startup employees who exercise incentive stock options and trigger the federal AMT. It's less severe than California's 7% state AMT, but it exists and affects ISO planning.

This guide covers how Colorado taxes each type of equity compensation, the AMT implications for ISO holders, what happens when you move from California, and how to plan around the state's rules.

Colorado's tax structure for tech employees at a glance

RSUs in Colorado

At vest: ordinary income taxed at 4.4%

When RSUs vest, the fair market value at the vesting date is ordinary income — taxed federally at your marginal rate (22–37% depending on total comp) and by Colorado at 4.4%. Your employer typically withholds at the IRS 22% supplemental rate federally and at 4.4% for Colorado. For senior engineers with marginal federal rates of 32% or 37%, the 22% federal withholding creates a shortfall that you'll owe at tax time. See the RSU after-tax calculator and RSU tax planning guide for details on managing this gap.

Example: a Palantir engineer in Denver vests $180,000 of RSUs in 2026. Federal tax at 35% marginal rate = $63,000. Colorado state tax at 4.4% = $7,920. Total = $70,920. The shares' post-tax value — before any holding-period appreciation — is approximately $109,000.

After vest: capital gains taxed at the same 4.4%

Your cost basis in the shares is the FMV at vest. If you hold the shares after vesting and later sell at a higher price, the gain is a capital gain. Unlike at the federal level — where long-term gains (held 1+ year from vest) qualify for preferential 0/15/20% rates — Colorado applies the same 4.4% to short-term and long-term capital gains alike.

The practical implication: Colorado gives you no tax incentive to hold RSU shares for more than one year at the state level. The federal incentive still exists (the difference between 37% ordinary income and 20% long-term capital gains can be meaningful), but Colorado's arithmetic is neutral on the hold/sell decision post-vest.

ISOs and Colorado's state AMT

Colorado's state alternative minimum tax (Form DR 0104AMT) is the most important Colorado-specific tax item for startup employees exercising incentive stock options. Here's how it works:

How Colorado's AMT is calculated

Colorado computes an "alternative minimum tax" as the excess of 3.47% × Colorado alternative minimum taxable income (AMTI) over your regular Colorado tax. If that amount is positive, you owe the difference as additional Colorado tax.

Colorado's AMT mirrors the federal AMT structure: the ISO bargain element (FMV at exercise minus your strike price) is an AMT preference item that adds to AMTI. This means exercising ISOs can trigger Colorado AMT — even if you don't sell the shares.

Colorado AMT vs California AMT: a meaningful difference

Concretely: a Boulder startup engineer exercises ISOs with a $400,000 bargain element (FMV − strike price) in 2026. Federal AMT on that spread is approximately $104,000 (26% on the first $239,100 of AMT income, 28% above that, after exemptions). California AMT on the same spread would add another $28,000. Colorado AMT would add approximately $13,880 (3.47% × $400K, reduced by regular CO tax already paid on other income).

Colorado's AMT is roughly half of California's — significant, but not catastrophic. For startup employees comparing Colorado vs. California for ISO exercise strategy, Colorado is materially better. For startup employees comparing Colorado vs. Washington, Texas, or Florida, Colorado still has real ISO tax friction to plan around.

The ISO AMT calculator models federal AMT and lets you compare the state layer for ISO exercise planning.

Qualifying vs. disqualifying dispositions in Colorado

• Qualifying disposition (hold ≥2 years from grant AND ≥1 year from exercise): the spread at exercise is ISO income for federal AMT — same Colorado AMT impact. The gain at sale is federal long-term capital gain taxed at 0/15/20%. At the Colorado level, that gain is taxed at 4.4% (no LTCG preference).
• Disqualifying disposition (sell before holding periods met): the spread becomes ordinary income federally and for Colorado at 4.4%. No federal AMT preference; no Colorado AMT on a disqualifying disposition. Remaining appreciation (above the spread) is a short-term capital gain — also taxed at 4.4% by Colorado.

NSOs in Colorado

Non-qualified stock options are taxed at exercise: the spread (FMV at exercise minus strike price) is ordinary income, taxed by Colorado at 4.4%. There is no state AMT event for NSOs. Post-exercise appreciation held over one year is a long-term capital gain — but again, Colorado applies the same 4.4%, so there is no Colorado-specific incentive to delay the sale.

ESPP in Colorado

Employee Stock Purchase Plans (§423 qualifying plans) follow the same federal structure, with Colorado taxing all income components at 4.4%:

• Disqualifying disposition: ordinary income component (the discount, including any look-back benefit) is taxed at 4.4% in Colorado; any additional short-term gain is also 4.4%.
• Qualifying disposition: the 15% discount (possibly enhanced by the look-back) is ordinary income at 4.4%; appreciation above that is a long-term capital gain — taxed at 4.4% by Colorado (same rate).

See the ESPP guide and ESPP calculator for after-tax modeling across both disposition types.

Moving from California to Colorado: what changes for equity

The California-to-Colorado move is a common path for tech workers attracted by lower costs of living, outdoor lifestyle, and — yes — lower state taxes. The tax savings on equity compensation can be substantial, but there's an important catch: California's long-arm sourcing rules don't stop at the state line.

California long-arm sourcing still applies to old grants

California taxes RSU income based on the proportion of the grant-to-vest period you spent working in California — regardless of where you live when the shares vest. If you spent 3 of 4 vesting years in California and then moved to Colorado before the final vest, California claims 75% of that vest as California-source income. Colorado also taxes the income based on its apportionment rules (time worked in Colorado during the grant-to-vest period).

This can create double-state-tax exposure on the same income — partially offset by credits — for equity granted while you were a California resident. The California equity tax guide and the remote work state tax guide cover the sourcing mechanics in detail.

Income tax savings after the move

The combined state tax savings on ordinary income (RSU vests, salary, bonus) for a senior engineer moving from California to Colorado range from $15,000 to $30,000+ per year depending on total comp. Unlike Washington, Colorado still has state income and capital gains tax — just at a much lower rate than California.

Colorado's capital gains subtraction: does it help tech employees?

Colorado has a "Capital Gain Subtraction" (C.R.S. § 39-22-518) that allows up to $100,000 of capital gain to be subtracted from Colorado taxable income annually. The catch: it applies only to capital gains from the sale of qualifying Colorado tangible personal or real property held for at least five continuous years.⁵

This subtraction does not apply to:

• Employer stock (RSUs, ESPP, options) held outside the five-year tangible property window
• Publicly traded securities generally
• Financial instruments

For most tech employees, the Colorado capital gains subtraction is irrelevant to equity compensation. Don't plan around it for RSU or option income.

Planning strategies for Colorado tech employees

1. Model ISO exercise in tranches to manage Colorado AMT

Colorado's 3.47% AMT is real but manageable. Because Colorado AMT is the excess of 3.47% × CO AMTI over your regular CO tax, you effectively owe AMT only to the extent the ISO spread pushes your liability above your regular rate. Exercising ISOs in tranches across multiple tax years — rather than all at once — spreads the AMT hit and keeps each year's exposure smaller. Use the ISO AMT calculator to model the exact breakeven exercise amount for your situation.

2. Don't over-optimize for the LTCG hold period at the state level

The federal tax benefit of holding RSU shares 12+ months (ordinary income rates → 0/15/20% LTCG) is real and worth capturing. But don't let the Colorado state tax picture push you to over-hold concentrated employer stock — Colorado gives you no additional incentive at the state level for the longer hold. Decisions about when to sell concentrated RSU positions should be driven by concentration risk, federal LTCG savings, and your personal liquidity needs — not Colorado's neutral treatment of holding periods.

3. Use a DAF for appreciated employer stock

If you have meaningful charitable intent, donating appreciated RSU shares (held 12+ months from vest) directly to a donor-advised fund eliminates the federal capital gain tax event — and since there's no Colorado realization event either, the Colorado 4.4% gain tax is also avoided. You get a federal deduction for the full fair market value. This strategy is covered in detail in the DAF guide.

4. Max retirement accounts to reduce Colorado taxable income

Colorado taxes income, but not distributions from traditional retirement accounts when taken in retirement (if you've moved to a lower-tax state). Every dollar deferred into a traditional 401(k) reduces your current Colorado taxable income at 4.4%. Adding after-tax Mega Backdoor Roth contributions builds Roth assets that are never subject to Colorado income tax on withdrawal. See the Mega Backdoor Roth calculator and tech employee retirement planning guide.

5. Time RSU sales and CA long-arm exposure

If you recently moved from California and have equity grants that were partially vested in California, get the grant-to-vest day-count calculation done before your first Colorado vest event. The CA sourcing determination affects both your CA and CO returns, and it changes annually as new vesting tranches occur. A tax advisor who handles multi-state equity sourcing can prevent you from both double-paying and under-reporting.

What a fee-only advisor can help you model

• The optimal ISO exercise amount each year to stay below Colorado's AMT trigger while still building equity value
• Whether CA long-arm sourcing still applies to your specific grants — and by how much — after a California-to-Colorado move
• RSU lot selection for tax-loss harvesting and concentrated stock risk reduction while minimizing Colorado state tax
• Year-by-year retirement account stacking (401k + Mega Backdoor Roth + HSA) to reduce Colorado ordinary income
• DAF strategy if you have charitable intent and concentrated appreciated employer stock