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Iowa · rsu tax

RSU taxes in Iowa: withholding, supplemental wages, and state nexus

How Iowa's 3.8% top marginal rate interacts with supplemental-wage withholding on RSU vesting, and what to do when your RSUs vest after a move.

What Iowa residents actually pay

Iowa taxes ordinary income at a top marginal rate of 3.8%. 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.

Employee stock gains from Iowa corporations may qualify for exclusion under specific conditions.

Withholding gap

Federal supplemental-wage withholding on RSU vesting is flat — 22%, rising to 37% once year-to-date supplemental wages exceed $1M. If your actual marginal rate is higher, the shortfall shows up at filing. In Iowa, layer on 3.8% at the top and model what you'll owe before year-end.

Sourcing when you move

If you earned part of a vesting tranche while in a different state, most high-tax states (California, New York, Massachusetts) use workday allocation between grant and vest. Your payroll will likely withhold only for your current state, so a manual true-up at filing is the rule, not the exception.

Frequently asked

Does Iowa tax RSU income the same as wages?
Yes. Iowa treats RSU ordinary income as wages, taxable at the state's top marginal rate of 3.8%. 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 Iowa?
Iowa 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 Iowa 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 Iowa move, expect the old state to tax the portion of each tranche attributable to workdays earned there. Iowa taxes the remainder.
Can I reduce Iowa taxes by timing my RSU sales?
Iowa gives preferential treatment to long-term capital gains. Holding RSU shares 12+ months past vest can produce both federal and state savings. Weigh concentration risk before using this as a reason to hold.

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