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Idaho · rsu vesting

RSU vesting schedules in Idaho: cadence, withholding, and annual tax cycle

A quarter-by-quarter guide to managing RSU vests as a Idaho resident: 5.8% state marginal rate, workday sourcing after moves, and the three withholding events every year.

What Idaho residents actually pay

Idaho taxes ordinary income at a top marginal rate of 5.8%. 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.

Flat 5.8% state tax as of 2023.

The vest-day mechanics

On each vest date, shares settle at the closing price and the full value adds to W-2 wages. Your employer runs federal supplemental withholding at 22% (37% above $1M YTD supplemental) plus 5.8% state withholding at the Idaho top bracket, plus Medicare and Social Security up to the wage base.

Quarterly cadence

A typical four-year, quarterly-cliff RSU grant produces 16 vesting events. Each one is a supplemental-withholding event at the same statutory rates, which means your under-withholding gap compounds across the year if your marginal bracket is above 22%. Model it per tranche, not per year.

Three scheduled planning windows

Three times a year the math is worth re-running: after the Q1 vest (when you can see YTD withholding trajectory), before the Q3 vest (when you set up Q4 estimates or adjust W-4), and in December (final true-up plus the decision to hold or sell the year's accumulated shares).

Frequently asked

Does Idaho tax RSU income the same as wages?
Yes. Idaho treats RSU ordinary income as wages, taxable at the state's top marginal rate of 5.8%. 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 Idaho?
Idaho 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 Idaho 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 Idaho move, expect the old state to tax the portion of each tranche attributable to workdays earned there. Idaho taxes the remainder.
Can I reduce Idaho taxes by timing my RSU sales?
Idaho 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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