If you're a founder or early investor in a Washington-based startup, this is probably the first question you asked when Governor Ferguson signed ESSB 6346 into law: does my Section 1202 exclusion still protect me from the new 9.9% state income tax?
The short answer is yes — because Washington’s income tax starts from federal AGI, and QSBS gains excluded under Section 1202 never reach AGI. But the details matter, and you need to understand the risks before you rely on this entirely. (For background on Section 1202 and how QSBS works, see my QSBS guide.)
How Washington's income tax (ESSB 6346) base works
ESSB 6346 imposes a 9.9% tax on Washington taxable income above $1 million per household, starting January 1, 2028. The critical structural feature is that the tax starts with federal adjusted gross income (AGI) as its base.
This is the key to the QSBS Washington tax question.
Section 1202 excludes qualifying gain from federal gross income — not from AGI, not as a deduction, not as a credit. The exclusion happens upstream of AGI entirely. Gain that qualifies for the Section 1202 exclusion is never included in your federal gross income, which means it never flows into federal AGI, which means it never enters Washington's tax base.
In other words: there is nothing for Washington to tax.
The rule: If gain is excluded under Section 1202, it never enters federal AGI — and Washington’s 9.9% income tax starts from AGI. No AGI, no Washington tax.
A concrete example
Suppose you're a founder who sells your qualified small business stock in 2029 for $12 million. Your basis is $1,000 — you incorporated the company, paid nominal consideration for your shares, and held them for six years. Your gain is $11,999,000.
If the stock qualifies as post-OBBBA QSBS (issued after July 4, 2025) and you've held it for at least five years, you can exclude up to $15 million of gain per issuer under Section 1202.
Here's what the math looks like:
With QSBS exclusion:
- Gain: ~$12 million
- Section 1202 exclusion: ~$12 million (within the $15M cap)
- Amount included in federal AGI: $0
- Washington taxable income from this sale: $0
- Washington income tax on this gain: $0
Without QSBS exclusion (same sale, no qualifying stock):
- Gain: ~$12 million
- Federal AGI includes the full ~$12 million
- Washington taxable income: ~$12M minus $1M standard deduction = ~$11 million
- Washington income tax: ~$11M × 9.9% = ~$1,089,000
| Scenario | Federal AGI | WA Taxable Income | WA Tax |
|---|---|---|---|
| With QSBS exclusion | $0 | $0 | $0 |
| Without QSBS exclusion | ~$12M | ~$11M | ~$1,089,000 |
That’s over a million dollars in Washington state tax saved — on top of the federal tax savings from Section 1202.What about the capital gains tax interaction?
Washington also has a separate 7% long-term capital gains tax (the excise tax upheld by the state Supreme Court in 2023). ESSB 6346 specifically provides a credit for capital gains tax already paid, to prevent double taxation on the same gains.
But for QSBS holders, this interaction is mostly academic. QSBS gains excluded under Section 1202 are not subject to Washington's capital gains tax either — that tax also starts from federal long-term capital gain, and excluded gains aren't in the federal number. So there's no double taxation issue because there's no single taxation issue. The gains fall outside both taxes.
Why this isn't as settled as it sounds
I want to be careful here. The analysis above is correct under the plain language of the statute as enacted. But there are reasons to stay alert:
The legislature tried to close this door. During the 2026 session, SB 6229 (and companion HB 2292) would have required taxpayers to add back federally excluded QSBS gains when calculating Washington's capital gains tax. The bill did not pass — it died without advancing. But the fact that it was introduced tells you that legislators are aware of the QSBS Washington tax gap and may revisit it.
Administrative guidance hasn't been issued. The Department of Revenue has not yet published rules or guidance specifically addressing Section 1202 exclusions under the new income tax. When it does, the treatment could introduce complications — particularly around reporting, documentation, or the interaction between the income tax and the capital gains tax.
The statute could be amended before 2028. The tax doesn't take effect until January 1, 2028. The legislature has two more sessions (2027 and 2028) to modify the statute before the first dollar is owed. An add-back provision for QSBS gains — similar to what several other states have adopted — is a real possibility.
Judicial or interpretive risk. Even though the statutory text is clear, Washington’s courts have shown a willingness to accept creative characterization arguments in the tax context — the capital gains excise tax ruling being the most prominent example. The risk is low, but it’s not zero. The state could argue for sourcing mechanics or characterization differences that complicate the straightforward AGI analysis.
Oregon now decouples. Washington currently does not. Oregon’s SB 1507, enacted in 2026, means Oregon residents who sell QSBS may owe full state income tax on gains excluded federally. If you have ties to both states, the contrast matters — and it shows that the assumption “QSBS is safe at the state level” may not last.
If you hold QSBS or expect to in the future, here's what to think about now:
Confirm your stock actually qualifies. Section 1202 has specific requirements: the stock must be in a domestic C corporation, acquired at original issuance, the corporation must meet the $75 million gross asset test (post-OBBBA) at the time of issuance, and the corporation must be engaged in a qualified active business. Many founders assume they qualify without confirming. Don’t. If you’re unsure whether your stock qualifies, this is worth checking before you assume a zero state tax outcome.
Track your holding period carefully. Under the OBBBA's new tiered structure, you need five years for the full 100% exclusion. Three years gets you 50%, four years gets you 75%. The difference between a four-year and five-year hold on a $12 million gain is roughly $590,000 in federal tax — and potentially the difference between owing Washington’s 9.9% income tax or not.
Consider exclusion multiplication. If your expected gain exceeds the $15 million per-issuer cap, gifting QSBS to family members or transferring to non-grantor trusts can create additional exclusion buckets. Each separate taxpayer — spouse, adult child, qualifying trust — gets their own $15 million cap. For a detailed walkthrough, see my post on QSBS and trusts and estates strategies.
Watch the 2027 legislative session. If Washington introduces a QSBS add-back provision, the calculus changes entirely. This is the single most important variable for QSBS holders in Washington between now and 2028.
Don't confuse this with domicile planning. Even if your QSBS gain is fully excluded, your other income — salary, bonuses, S corp distributions, partnership income — may still be subject to the 9.9% tax. If your total AGI exceeds $1 million from non-QSBS sources, you'll owe the tax on that income regardless. For a complete guide to domicile and residency planning, see Washington State Income Tax Planning (2026–2028): Complete Guide for High Earners.
The bottom line
Under ESSB 6346 as currently enacted, QSBS gains excluded under Section 1202 should not be subject to Washington's new 9.9% income tax. The exclusion operates at the federal gross income level — upstream of AGI — so excluded gains never enter the state's tax base.
But this is today's answer. The legislature tried to change it once already, Oregon just closed the same door for its residents, and the Department of Revenue hasn't weighed in yet. If you're planning around QSBS in Washington, build your plan on the current law but watch the horizon closely.
For the full picture on Washington's new income tax, see Washington's New Income Tax: What Founders, Investors, Athletes, and High Earners Need to Know.Frequently Asked Questions
Does Section 1202 protect me from Washington's capital gains tax too?
Yes. Washington's 7% capital gains excise tax is calculated from federal net long-term capital gain. Gains excluded under Section 1202 are excluded from federal gross income and therefore don't appear in the capital gains tax base either. You're outside both taxes on the excluded portion.
What if my QSBS gain exceeds the $15 million per-issuer cap?
The gain above the cap is included in federal gross income, flows into federal AGI, and would be subject to Washington's 9.9% income tax (assuming your total AGI exceeds the $1 million threshold). This is why exclusion multiplication through gifting and trusts is worth planning for — see QSBS Is Alive and Well in Washington State for the planning framework.
Could Washington add a QSBS add-back provision later?
Yes. SB 6229 attempted exactly this in 2026 and failed, but the legislature could revisit it in 2027 or 2028. Oregon enacted a similar provision (SB 1507) in 2026. This is not a theoretical risk.
I have QSBS gains and other income over $1 million. How does that work?
Only the QSBS-excluded portion escapes the tax. Your other income — salary, bonuses, business income, non-QSBS investment gains — counts toward the $1 million threshold and is taxed at 9.9% above that line. The Section 1202 exclusion only shields the qualifying gain itself.
Does the OBBBA's new $15 million cap apply to my existing stock?
No. The increased cap applies only to stock issued after July 4, 2025. Stock issued before that date is subject to the original $10 million cap (or 10x adjusted basis, if greater). Check your issuance date.
What if the law changes before I sell?
You’re exposed. The Section 1202 exclusion protects you under the current statute, but if Washington adds an add-back provision before your sale, your excluded gain could become taxable at the state level. Planning should assume change risk — don’t lock in a strategy that only works if the 2026 statute stays untouched through 2028 and beyond.
Does Washington conform to Section 1202?
Yes, for now. ESSB 6346 uses federal AGI as its starting point and does not add back any Section 1202 excluded gains. Unlike Oregon (which enacted SB 1507 to decouple from Section 1202 in 2026), Washington currently conforms to the federal treatment. But this conformity is statutory, not constitutional, and the legislature could change it at any time.
Can Washington change this before 2028?
Yes. The tax doesn't take effect until January 1, 2028, and the legislature has sessions in both 2027 and 2028 to amend ESSB 6346. A QSBS add-back provision (similar to Oregon's SB 1507) could be added at any point before or after the effective date. This is the most important variable to monitor if you're planning a QSBS exit in Washington.
