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Washington State Stock Options Tax: What Amazon and Microsoft Employees Need to Know

Washington is home to Amazon and Microsoft — two of the largest concentrations of employee stock options in the world. Most Washington employees know the state has no income tax. What fewer know is that Washington imposes a capital gains excise tax that catches ISO qualifying dispositions, and that a new millionaires' income tax arrives in 2028 that will fundamentally change the calculus for high earners. Four facts define the Washington landscape:

  1. No state income tax — currently. NQSO exercises and RSU vesting create ordinary income, which Washington does not tax. This is a major advantage over California (13.3%) and New York (up to 10.9%).
  2. Capital gains excise tax catches ISO qualifying dispositions. Washington imposes a 7% excise tax on long-term capital gains above $278,000 (2025 standard deduction; inflation-adjusted annually), and 9.9% on gains above $1,000,000. ISO qualifying dispositions produce long-term capital gains and are subject to this tax.1
  3. Washington conforms to §1202 QSBS. Unlike California, Washington respects the federal QSBS exclusion — a qualifying small business stock gain excluded federally is also excluded from Washington's capital gains tax and (based on current law) the future income tax.2
  4. A millionaires' income tax arrives January 1, 2028. ESSB 6346, signed March 30, 2026, imposes a 9.9% income tax on household income above $1,000,000. After 2028, NQSO exercises and RSU vesting above the threshold will be taxed at state level for the first time.3

Here's how each plays out in practice — and why the right pre-2028 exercise strategy is often the opposite of what California employees assume.

Federal vs Washington Treatment: Direct Comparison

Event Federal Tax Treatment Washington Treatment (2026–2027)
ISO exercise Spread is AMT preference item — no regular income tax. May trigger federal AMT at 26–28%. No WA income tax at exercise. WA has no AMT. The ISO spread is irrelevant to WA until shares are sold.
NQSO exercise Spread is ordinary income (W-2) — federal rates up to 37% + 3.8% NIIT on MAGI above thresholds No WA income tax. Washington currently does not tax ordinary income. The NQSO spread costs 0% at state level in 2026–2027.
ISO qualifying disposition Entire gain taxed at LTCG rates (15% or 20%) + possible 3.8% NIIT WA capital gains excise tax applies. Gains above $278,000 (2025 standard deduction) taxed at 7%. Gains above $1,000,000 taxed at 9.9%.1
ISO disqualifying disposition Spread at exercise = ordinary income (W-2). Post-exercise gain = short- or long-term capital gain. Ordinary income component: No WA tax. Post-exercise LTCG (if held >1 yr from exercise): subject to WA CGET above standard deduction.
RSU vesting FMV at vest is W-2 ordinary income — employer withholds federal tax No WA income tax. RSU income is ordinary income — state tax is $0 in 2026–2027.
QSBS gain (§1202) 50–100% exclusion depending on holding period and OBBBA tier (up to $15M exclusion) WA conforms. Federally excluded QSBS gains are also excluded from WA capital gains excise tax.2

The NQSO Advantage: Washington's Biggest Edge Over California

When a Washington employee exercises NQSOs, the spread is ordinary income — and Washington does not tax ordinary income. That's it. No form to file, no state withholding, no estimated payment. Compare this to California (up to 13.3% on the same income) or New York (up to 10.9% state + NYC).

For a senior Amazon or Microsoft employee exercising $500,000 in NQSO spread, the California comparison alone is stark:

NQSO exercise — $500,000 spread Washington California
Federal ordinary income tax (approx. 35% bracket) ~$175,000 ~$175,000
State income tax on the spread $0 ~$61,500 (at 12.3%)
Total state + federal ~$175,000 ~$236,500

The same RSU math applies: a $300,000 vest costs a California employee roughly $37,000 in state tax that a Washington employee doesn't pay.

The ISO Trap: Qualifying Dispositions Trigger WA Capital Gains Tax

Here's where Washington diverges from what most employees expect. ISO qualifying dispositions — usually considered the gold-standard outcome — produce long-term capital gains. And Washington's capital gains excise tax applies to long-term capital gains above its standard deduction.

For 2025, the standard deduction is $278,000 (indexed annually for inflation from a $250,000 base).1 Gains below this threshold are fully exempt. Gains above it are taxed at 7% up to $1,000,000 and 9.9% above $1,000,000 — a tiered structure enacted via SB 5813, retroactive to January 1, 2025.

Example. A Microsoft employee has 10,000 ISOs, $40 strike, FMV at exercise $140. She exercises, waits to satisfy the qualifying-disposition hold periods (2yr from grant, 1yr from exercise), then sells at $160.
  • Federal: $1,200,000 long-term capital gain ($120/share × 10,000 shares). At 20% federal LTCG + 3.8% NIIT = ~$286,800 federal tax.
  • Washington capital gains excise tax: $1,200,000 − $278,000 standard deduction = $922,000 taxable. First $1,000,000 tier: $922,000 × 7% = $64,540 WA CGET.
  • Total state + federal: ~$351,340.

Contrast: if she had exercised and sold the same day (disqualifying disposition), the $1,000,000 spread would be ordinary income at federal rates — and $0 WA state tax. Federally worse (37% vs 20% LTCG), but $64,540 in WA tax avoided. The right answer depends on the specific numbers.

The Counterintuitive ISO vs NQSO Comparison in Washington

In California, ISOs are often worse than NQSOs at state level — CA taxes ISO exercise spreads as ordinary income. In Washington, the opposite distortion exists: ISO qualifying dispositions (LTCG) are taxed by the state; NQSO exercise spreads (ordinary income) are not.

This creates a counterintuitive pre-2028 planning insight for Washington employees who hold both ISOs and NQSOs:

For employees below the $278,000 CGET standard deduction (smaller positions, exercising in tranches), qualifying dispositions remain clearly better — no WA tax and federal LTCG rates. For large positions where LTCG will exceed the standard deduction significantly, the 7–9.9% WA CGET may or may not offset the federal rate advantage, depending on your marginal rate and the size of the gain. A specialist advisor will model both paths.

QSBS: Washington Conforms (Unlike California)

For Washington employees with pre-IPO startup equity that qualifies under IRC §1202, the state tax picture is favorable. QSBS gains that are federally excluded are also excluded from Washington's capital gains excise tax — a direct contrast with California, which taxes QSBS gains as ordinary income at state level regardless of federal exclusion.2

Under OBBBA (July 2025), the federal QSBS exclusion is now $15,000,000 per issuance, with tiered rates: 50% at 3 years, 75% at 4 years, 100% at 5 years. A Washington founder with a qualifying exit could exclude up to $15M of gain federally and have none of that gain reach Washington's capital gains tax base.

Legislative risk. Washington's QSBS conformity is statutory, not constitutional. Bills SB 6229 and HB 2292 (2026 session) would have required taxpayers to add back federally excluded QSBS gains — they failed, but they signal legislative intent. Founders with pending exits should monitor future sessions and consider whether the timing of a sale is affected by this risk.4

The 2028 Warning: ESSB 6346 Changes Everything for High Earners

Washington Governor Ferguson signed ESSB 6346 on March 30, 2026. Starting January 1, 2028, Washington imposes a 9.9% income tax on household income above $1,000,000.3 This changes the math for high-earning Amazon and Microsoft employees in three ways:

  1. NQSO exercises above $1M household income will be subject to 9.9% WA income tax on the portion above the threshold. A $1.5M NQSO spread in 2028 means $500,000 × 9.9% = $49,500 in WA tax that doesn't exist in 2026 or 2027.
  2. RSU vesting above $1M will similarly be subject to the income tax. Amazon engineers with large RSU grants should model multi-year vesting schedules to avoid unnecessary clustering of income above the threshold.
  3. ISO qualifying dispositions will still be subject to the capital gains excise tax, not the income tax — capital gains are treated as capital gains under the new law. In this post-2028 world, qualifying dispositions regain their traditional tax advantage over disqualifying dispositions for high earners (LTCG taxed at 9.9% CG rate vs ordinary income taxed at the same 9.9% income tax rate, but federal LTCG rates are 20% vs 37%).

The window to exercise NQSOs and capture RSU income without any WA state tax closes December 31, 2027. If you have large exercises planned, a specialist advisor can help you model whether to accelerate into 2026–2027 or spread across years after the tax takes effect.

Remote Work and Sourcing: California Workaholics and WA Residents

Washington has no workday-based sourcing formula for options (unlike California, which sources ISO/NQSO gains to days worked in California). If you live in Washington and your options were granted while you worked in Washington, WA sourcing is straightforward.

Two situations create complexity:

Six Planning Strategies for Washington Stock Option Holders

  1. Exercise NQSOs before 2028. There's no WA state tax on ordinary income until January 1, 2028. Large NQSO exercises — especially multi-million-dollar spreads — should be modeled for execution in 2026 or 2027 before the 9.9% income tax arrives. Coordinate with your RSU vesting schedule to avoid unnecessary clustering.
  2. Use the CGET standard deduction for ISO qualifying dispositions. The annual standard deduction (~$278,000 for 2025, inflation-adjusted for 2026TODO-verify: 2026-07-01 — confirm 2026 WA CGET standard deduction from dor.wa.gov) exempts the first $278K+ of LTCG from WA CGET. For smaller ISO positions, exercising in tranches to keep annual LTCG under the deduction is a legitimate strategy.
  3. Model disqualifying disposition vs qualifying disposition. For large ISO positions, run the math: qualifying disposition (federal LTCG rate + WA CGET) vs disqualifying (federal ordinary rate + $0 WA income tax until 2028). The break-even depends on your marginal federal rate and the size of the position.
  4. Protect QSBS status now, before the legislature acts. If you have pre-IPO equity that qualifies under §1202, your QSBS exclusion is worth up to 7–9.9% at the WA level — but only if current conformity holds. Structure your exit and holding periods before SB 6229-style legislation passes in a future session.
  5. Plan around the $1M threshold post-2028. After 2028, household income above $1M is taxed at 9.9%. If your RSU vesting + salary already approaches $1M, an NQSO exercise that pushes you to $1.5M generates 9.9% WA tax on only $500K — not the full $1.5M. Tax spreading across years (if your company allows alternative exercise schedules) matters more after 2028 than it does today.
  6. Don't assume your CA options are WA-clean. If you vested options while working in California — even a few months on a CA assignment — California asserts a workday sourcing claim. A specialist advisor should confirm whether any pre-move vesting creates a CA filing obligation before you treat the income as purely WA.
Why a Washington-specific specialist matters. Amazon and Microsoft have specialized equity plans — RSU cliff vests, MSPP, different NQSO exercise windows — and the WA/federal interaction (especially the 2028 deadline) creates planning decisions that few generalist advisors have modeled. A specialist who has worked with dozens of Redmond or Bellevue employees knows these patterns.

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Sources

  1. Washington Department of Revenue, Capital Gains Tax, dor.wa.gov/taxes-rates/other-taxes/capital-gains-tax. Standard deduction $278,000 for tax year 2025 (inflation-adjusted annually from the $250,000 base under RCW 82.87.060). Tiered rates: 7% on gains above the standard deduction up to $1,000,000; 9.9% on gains above $1,000,000 per SB 5813 (2025, retroactive to January 1, 2025). New tiered-rate notice: dor.wa.gov — New tiered rates notice.
  2. Washington QSBS conformity: WA capital gains excise tax applies to the same gains as federal long-term capital gains and does not add back §1202 excluded amounts. SB 6229 / HB 2292 (2026 session), which would have required QSBS add-back, did not pass. Current conformity analysis via Carney Badley Spellman (2026).
  3. ESSB 6346, signed by Governor Ferguson, March 30, 2026. Imposes 9.9% tax on household income above $1,000,000, effective January 1, 2028. See Morgan Lewis summary (March 2026).
  4. SB 6229 / HB 2292 bill report (2026 session), Washington Legislature: would have required adding back §1202-excluded QSBS gains to Washington's capital gains tax base. Bills failed in 2026 session but indicate ongoing legislative interest in closing QSBS conformity. SB 6229 bill report (PDF).

Values verified May 2026. Washington state tax law is changing rapidly — the 2026 standard deduction is inflation-adjusted by DOR (confirm current year at dor.wa.gov before filing). The 2028 income tax may be subject to legal challenge. Confirm all values with a qualified Washington state tax advisor before making irreversible decisions.