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Illinois · moving with-equity

Moving to or from Illinois with unvested equity: trailing nexus rules

How Illinois sources RSU, ISO, and NSO income when vesting straddles your move. Covers workday-allocation, grant-to-vest rules, and what to tell your payroll team.

What Illinois residents actually pay

Illinois taxes ordinary income at a top marginal rate of 4.95%. 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.

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The trailing nexus problem

You move out of a high-tax state. Your RSUs keep vesting. Who gets to tax them? In most states with nonresident-income rules, the answer is: both, on a workday-allocation basis. A tranche vesting today, covering a grant made before you moved, is split between your old state and your new one in proportion to workdays.

What to tell payroll

Employer payroll systems will usually withhold for your current work state only. That's technically wrong if any portion was earned in the prior state. The correction happens at filing, via nonresident returns and a resident credit for taxes paid elsewhere.

Frequently asked

Does Illinois tax RSU income the same as wages?
Yes. Illinois treats RSU ordinary income as wages, taxable at the state's top marginal rate of 4.95%. 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 Illinois?
Illinois 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 Illinois 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 Illinois move, expect the old state to tax the portion of each tranche attributable to workdays earned there. Illinois taxes the remainder.
Can I reduce Illinois taxes by timing my RSU sales?
Illinois 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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