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Colorado · iso amt

ISO exercises and AMT in Colorado

Colorado does not run a separate state AMT. Federal AMT still applies on your ISO bargain element; we walk through the interaction.

What Colorado residents actually pay

Colorado taxes ordinary income at a top marginal rate of 4.4%. RSU settlement value, NSO exercise spread, and ESPP discount income all count as ordinary wages for this purpose and flow through the state's normal brackets.

Flat 4.4% state rate. Denver has become a meaningful secondary tech hub.

Federal AMT on the bargain element

Exercising ISOs and holding the shares creates AMT "preference income" equal to the spread between fair market value at exercise and your strike price. That's the bargain element. It doesn't show up on a W-2, and many people discover it only when their CPA calculates AMT in April.

Frequently asked

Does Colorado tax RSU income the same as wages?
Yes. Colorado treats RSU ordinary income as wages, taxable at the state's top marginal rate of 4.4%. Supplemental-wage federal withholding (22%, or 37% above $1M YTD) does not adjust for state withholding, so you often owe extra at filing.
What happens if I exercise ISOs while living in Colorado?
Colorado does not run a separate state AMT, so only federal AMT applies. You still need to model the bargain element carefully if you plan a cashless exercise-and-sell.
I moved to Colorado from another state. Who taxes my vesting RSUs?
Most high-tax states (CA, NY, MA) source RSU ordinary income to workdays between grant and vest. If your grant pre-dates your Colorado move, expect the old state to tax the portion of each tranche attributable to workdays earned there. Colorado taxes the remainder.
Can I reduce Colorado taxes by timing my RSU sales?
Colorado taxes long-term capital gains at the same rate as ordinary income, so timing alone does not produce a state savings — only federal. Holding for 12 months still halves the federal rate on gains above basis.

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