Washington State Capital Gains Tax: A 2026 Guide for Founders & Investors

Last updated: June 11, 2026

Washington has no personal income tax — yet. But it does have a standalone Washington State capital gains tax that hits founders, investors, and high earners hard at exit. Understanding this tax — its rates, its exemptions, its interaction with QSBS and residency rules, and the new 9.9% income tax arriving January 1, 2028 — is essential planning for anyone facing a liquidity event in Washington. This guide covers what the tax is, who pays it, what's exempt, and the legitimate ways to reduce or avoid it.

What Is Washington's Capital Gains Tax?

Washington's capital gains tax is a standalone excise tax on long-term capital gains realized by individual taxpayers. The tax was enacted in 2021, took effect in January 2022, and was upheld by the Washington Supreme Court in Quinn v. State, 1 Wn.3d 453, 526 P.3d 1 (2023). The U.S. Supreme Court denied certiorari in January 2024. The tax is structured as an excise — a tax on the privilege of selling assets — rather than as a tax on income, a structural choice the legislature made to avoid the constitutional uniformity-clause problem that has historically defeated Washington income tax proposals.

Is There a 2.9% Capital Gains Tax in Washington?

You may have seen references to a "2.9% capital gains tax." That figure is not a separate tax — it's the additional surcharge that SB 5813 layered on top of the original 7% rate for gains above $1 million. Add the 2.9 points to the base 7%, and you get the 9.9% top tier. So there is one capital gains tax with two tiers (7% and 9.9%), not a separate 2.9% tax. The confusion is understandable, because the legislature built the top tier as an add-on rather than a clean second bracket.

Rates and Thresholds (2026)

• Standard deduction: $278,000 for 2025, indexed annually for inflation (the 2026 indexed amount had not been published by the Washington DOR as of this update)
• 7% on long-term capital gains between the standard deduction and $1 million
• 9.9% on long-term capital gains exceeding $1 million

The 9.9% tier was added by SB 5813, signed by Governor Ferguson on May 20, 2025, retroactive to January 1, 2025. The $1 million threshold is not indexed for inflation — meaning more taxpayers will cross into the higher tier each year.

Note: This 9.9% capital-gains tier is part of the existing capital-gains excise tax. It is separate from the new 9.9% income tax (ESSB 6346) scheduled to take effect January 1, 2028, and the two taxes are governed by different statutory frameworks even though they share a rate.

What Two Real Exits Actually Cost

Numbers make this concrete. Assume a single filer, long-term gains, no real estate or QSBS exclusion:

• A $750,000 gain. Subtract the $278,000 deduction, leaving $472,000 — all in the 7% band. Tax: about $33,040.
• A $2,000,000 gain. Subtract the $278,000 deduction, leaving $1,722,000. The 7% base rate applies to all of it ($120,540); the 2.9% surtax applies to the $722,000 above $1,000,000 ($20,938). Total tax: about $141,478.
• A $5,000,000 gain that fully qualifies for the federal QSBS exclusion. Because the gain is excluded before it reaches your federal return, Washington never taxes it. Washington capital gains tax: $0 (see QSBS section below).

That last contrast — six figures versus zero — is why the planning sections below matter so much.

Who Pays the Tax?

The tax is imposed on individuals, not on corporations or LLCs directly. Pass-through gains, however, flow to the owners and count toward each owner's threshold. For married couples and registered domestic partners, the deduction and threshold rules require careful modeling — do not assume a sale can simply be split into two separate $1 million capital-gains tiers without reviewing filing posture, ownership, and Washington sourcing rules.

What Gains Are Subject to the Tax?

Long-term capital gains from the sale or exchange of:

• Stocks, bonds, and other securities
• Business interests (LLC interests, partnership interests, S-corp stock)
• Tangible personal property held for investment

What Gains Are Exempt?

• Real estate — direct sales of real property are excluded (but entity sales whose assets include real estate may not be)
• Retirement accounts — distributions from IRAs, 401(k)s, and similar plans
• Certain agricultural property
• Family-owned small business sales meeting specific conditions
• QSBS gains excluded under federal Section 1202 — for now (see below)

Do I Pay Capital Gains Tax If I Sell My House in Washington?

Generally, no. Gains from the direct sale of real property — your home, a rental, raw land you hold directly — are exempt from Washington's capital gains tax. The tax targets gains on financial assets and business interests, not real estate.

Two caveats matter. First, if you sell an entity (an LLC or partnership) whose assets include real estate, the look-through rules can pull some of that gain back into the tax — the real-estate exemption protects direct property sales, not the sale of a company that happens to own property. Second, people who are dealers in real property (holding it as inventory rather than investment) can be treated differently. For a straightforward sale of a home or investment property held in your own name, the exemption applies.

QSBS and Washington's Capital Gains Tax

Federal QSBS exclusion piggybacks into Washington's tax base. If you exclude a gain under Section 1202, Washington does not separately tax it — because the excluded gain never enters Washington's starting tax base. Washington computes its tax beginning with the taxpayer's federal long-term capital gain as reported on the federal return; gains excluded under Section 1202 are excluded before the federal return is filed, so they simply are not in the number Washington taxes.

That said, this is statutory conformity, not constitutional protection. Nothing in Washington's constitution requires the state to piggyback on federal AGI, and the legislature can change that at any time. SB 6229 in the 2026 session would have done exactly that — explicitly adding back federally excluded QSBS gains. It did not pass, but it came close enough to treat as a genuine warning shot.

→ Full guide: Washington's Capital Gains Tax and QSBS

How to Reduce or Avoid Washington's Capital Gains Tax

There is no single trick, but there are several legitimate planning levers. Which ones apply depends entirely on your facts, your timeline, and your tolerance for complexity. The biggest mistakes come from waiting until the deal is closing — most of these only work if they're in place before the sale.

Qualify for the QSBS exclusion. If your stock meets the Section 1202 requirements, the gain is excluded federally and therefore in Washington too. This is the single largest lever available to founders and early investors — frequently worth more than every other strategy combined. It has to be planned for from formation, not discovered at exit. See our complete QSBS guide. And if you do qualify, have a QSBS attestation letter prepared so the exclusion can be substantiated at exit.

Change your residency before you sell. Washington taxes residents. If you genuinely change both your domicile and your statutory residency before the sale closes, the gain may fall outside Washington's reach. Both tests apply independently, and late-stage moves are heavily scrutinized — see the residency section below.

Use the real-estate and family-business exemptions. Direct real property sales are exempt, and sales of qualifying family-owned small businesses can be too. Structuring a transaction to fit within an exemption is legitimate; assuming an exemption applies without confirming the conditions is where people get hurt.

Time the gain. The $1 million threshold and the standard deduction reset each year. Spreading a large gain across tax years — through an installment sale, staged secondary sales, or simply choosing when to close — can keep more of the gain in the 7% band instead of the 9.9% tier. Timing also interacts with the 2028 income tax (below): 2026 and 2027 may be meaningfully cheaper years to recognize income than 2028 and beyond.

Give appreciated assets to charity — carefully. Donating appreciated stock can remove the gain from your return entirely. But Washington's charitable deduction has a Washington-specific catch that disqualifies most national donor-advised funds (see below). Charitable remainder trusts and similar structures are also worth modeling for very large gains.

Gifting and trust planning. Transferring assets before a sale — to family members in lower brackets, or into properly structured trusts — can move gain outside your Washington tax picture. This overlaps with estate planning and has to be coordinated with Washington's estate tax, which is among the most aggressive in the country.

None of these is one-size-fits-all, and several carry real risk if executed sloppily or too late. The common thread: the planning has to happen before the transaction, not during it.

Residency Planning: Can You Move to Avoid the Tax?

For founders approaching a liquidity event, residency planning has become one of the highest-stakes tax issues in the entire transaction. Washington's residency rules under RCW 82.87.020 create two independent pathways to taxation:

1. Domicile-based residency — a fact-driven inquiry into where you actually live, intend to remain, and treat as your permanent home.
2. Statutory residency — maintaining a place of abode in Washington and being physically present in the state more than 183 days in the year.

A founder can trigger one without triggering the other. Both have to be analyzed independently. Late-stage relocations — moves attempted in the weeks before closing — are particularly risky and require careful documentation.

→ Full guide: Residency Planning Before You Sell

The Charitable Deduction Has a Hidden Catch

Washington's capital gains tax includes a charitable deduction under RCW 82.87.080 — but only for donations to "qualified organizations" that are eligible under IRC §170(c) and have their principal office in Washington. This is not a standard federal charitable deduction rule. It matters most for donor-advised funds: in Washington, the relevant organization is the DAF sponsor (Fidelity, Vanguard, Schwab, etc.), not the ultimate charity — and the major national DAF sponsors are not Washington organizations.

→ Full guide: Washington Capital Gains Tax Charitable Deduction

How and When to File and Pay

The Washington capital gains tax return is filed separately from, but alongside, your federal return. A few practical points:

• Electronic filing is mandatory. You file through the Washington DOR's My DOR portal (or approved tax-prep software), and you must attach a copy of your federal return and supporting documentation.
• Payment must be electronic — by electronic funds transfer or another DOR-authorized method such as credit card.
• Due date. The return normally tracks the federal deadline. For the 2025 tax year, the DOR moved the due date to May 1, 2026 (an extension tied to the December 2025 storms and flooding). That date has now passed. If you did not file or pay by May 1, 2026 and do not have a filing extension in place, penalties and interest are accruing — consult your advisor promptly.
• Extensions don't extend payment. You can obtain a filing extension to October 15, 2026 if you have a federal extension and request the Washington extension on time — but the tax itself is still due May 1, 2026. An extension to file is not an extension to pay.

The Tax Stack: What Happens in 2028

On January 1, 2028, Washington's new 9.9% income tax (ESSB 6346) takes effect on household income above $1 million. This is a separate tax from the capital gains excise — a true income tax under a separate statutory framework — and it applies to all forms of income, not just capital gains.

For founders and investors facing a near-term liquidity event, the implication is straightforward: 2026 and 2027 are likely the last two years to sell before the full weight of the Washington tax stack is in place. A high-income founder who closes a $5M exit in 2027 faces the current 9.9% capital gains tier. The same founder closing in 2028 faces that tier plus a 9.9% income tax on any other income above $1 million in the same year — a materially different planning environment.

The practical questions to be modeling now: Can the transaction close before January 1, 2028? If not, can it be structured to spread recognition across years? Does the 2028 income tax change the residency calculus? These questions don't have one-size-fits-all answers, but they have deadlines — and the deadline is getting closer.

→ Full guide: Washington's 9.9% Income Tax (ESSB 6346)

Legislative Timeline

• 2021: Original capital gains tax enacted
• 2022: Tax takes effect
• 2023: Washington Supreme Court upholds tax in Quinn v. State
• 2024: U.S. Supreme Court denies certiorari
• 2025: SB 5813 adds the 9.9% tier on gains over $1M (the "2.9% surcharge"), retroactive to January 1, 2025
• 2026: SB 6229 / HB 2292 (proposed QSBS add-back) fails to pass
• 2026: ESSB 6346 (9.9% income tax) enacted, effective January 1, 2028

Frequently Asked Questions

What is the Washington State capital gains tax rate? 7% on long-term capital gains between the $278,000 standard deduction (2025, indexed) and $1 million; 9.9% on gains exceeding $1 million. The $1 million threshold is not indexed for inflation.

Is there a 2.9% capital gains tax in Washington? Not as a separate tax. The 2.9% is the surcharge SB 5813 added on top of the 7% base rate for gains above $1 million, producing the 9.9% top tier. There is one capital gains tax with two tiers.

Do I pay Washington capital gains tax if I sell my house? Generally no. Direct sales of real property are exempt. But sales of entities that own real estate may be subject under look-through rules, and dealers in real property may be treated differently.

How can I avoid or reduce the Washington capital gains tax? The main legitimate levers are qualifying for the federal QSBS exclusion, changing residency before the sale, using the real-estate or family-business exemptions, timing the gain across tax years, and charitable or gifting strategies. Almost all of them must be in place before the sale closes.

When is the Washington capital gains tax due? For the 2025 tax year, returns and payment are due May 1, 2026 (a DOR extension tied to the December 2025 storms). A filing extension to October 15, 2026 is available with a federal extension, but the tax is still due May 1.

When did the Washington capital gains tax take effect? The tax took effect January 1, 2022. The Washington Supreme Court upheld it in Quinn v. State in 2023. The 9.9% tier on gains above $1 million was added by SB 5813 in 2025, retroactive to January 1, 2025.

Are QSBS gains subject to Washington's capital gains tax? Generally no. Washington piggybacks on federal capital gain as reported on the federal return, and Section 1202 excludes the qualifying gain before it reaches the federal return. But this is statutory conformity, not constitutional protection — SB 6229 in 2026 would have changed it, and similar legislation is likely to return.

Can I avoid Washington's capital gains tax by moving out of state? Possibly — if you change both your domicile and your statutory residency under RCW 82.87.020 before the sale closes. Both tests apply independently. Late-stage relocations are risky and require careful documentation.

Did Washington's capital gains tax survive court challenges? Yes. The Washington Supreme Court upheld the tax as a constitutional excise tax (not a property tax on income) in Quinn v. State, 1 Wn.3d 453 (2023). The U.S. Supreme Court denied certiorari in January 2024.

Have questions about your specific situation?

Joe Wallin is a startup and tax attorney with 25+ years of experience advising founders and investors on Washington tax planning, QSBS, and equity compensation. Book a free 20-minute call to discuss your situation.

This post is general information about Washington tax law, not legal or tax advice. Every situation is different — consult a qualified advisor before acting.