QSBS and Washington Residency: Timing Section 1202, the Sale, and the Move

For Washington founders approaching a sale, the 20-month window before ESSB 6346 takes effect is the single most important tax planning period of their career. The reason: three separate taxing systems — federal income tax, Washington's existing 7% capital gains tax, and the new 9.9% income tax — interact around a single event (the sale), and each one is sensitive to different planning variables.

This post walks through the interaction, with a focus on QSBS-qualifying stock. We cover the four levers that matter, the common sequencing mistakes, and the specific cases where a domicile change dramatically changes the math.

The four tax layers on a founder's sale

When a Washington-resident founder sells long-held C-corp stock in 2028, up to four taxes may apply:

1. Federal capital gains tax (0%, 15%, or 20%, plus 3.8% NIIT) — applies unless excluded under §1202.
2. Federal §1202 QSBS exclusion — removes federal gain (up to $10M or 10x basis) if all seven qualification tests are met.
3. Washington capital gains tax (7%) — applies to long-term capital gain in excess of a standard deduction (~$270K for 2024, indexed), with some federal conformity for §1202.
4. Washington income tax (9.9%) — applies to federal AGI over $1M per household starting 1/1/2028.

Each of these can attach, or not, depending on the facts. A properly planned sale closes with a minimum of layers attached.

§1202 in one paragraph

Section 1202 of the Internal Revenue Code excludes all federal capital gains tax on qualified small business stock held for at least five years, up to the greater of $10 million or 10 times the taxpayer's basis in the stock, per issuer. The stock must have been acquired at original issuance from a domestic C corporation that had gross assets of $50M or less at the time of issuance, with the corporation conducting an active trade or business (excluding certain industries — financial services, farming, personal services, hospitality, mining, and a few others). If all of those tests are met and the five-year hold is satisfied, the federal capital gains rate on the qualifying gain is zero. For founders who qualify, §1202 is the single most valuable provision in the Internal Revenue Code.

Because ESSB 6346's base is federal AGI and §1202 gain is excluded from federal gross income entirely, qualifying QSBS gain does not flow into the Washington income tax base either. The federal exclusion flows all the way through.

The four planning levers

1. Qualify the stock for §1202 to begin with

Many founders assume their stock is QSBS when it is not. Common disqualifiers include S-corp origination, stock received in a §351 exchange from an S-corp, stock acquired after the issuing corporation passed the $50M gross-asset test, or acquisition at secondary sale rather than original issuance.

This is a federal question, not a Washington question, but it is the first and most important filter. Stock that qualifies passes most of the rest of the analysis automatically. Stock that doesn't qualify has to run the full non-QSBS gauntlet below.

2. Satisfy the five-year hold

§1202 requires five years of holding. The five years is measured from the original issuance date, not from vesting or employment start. For founders whose five years expires in 2028, the math is clean: hold through the fifth anniversary and exclude. For founders whose five years expires in 2029 or 2030, there is a harder question: sell earlier (before the five-year mark, losing §1202 entirely) versus wait for the full exclusion. The answer depends on the deal-specific discount and the risk of waiting.

There is a specific trick worth mentioning: §1045 rollover. If a founder sells before the five-year mark but reinvests the proceeds in other QSBS within 60 days, the holding period tacks. This can rescue the §1202 treatment for founders forced into an early exit.

3. Time the sale relative to the Washington income tax effective date

For qualifying §1202 stock up to the $10M / 10x cap, the Washington income tax does not apply regardless of when you sell, because excluded gain is out of federal AGI. But for:

• Non-QSBS gain.
• QSBS gain in excess of the §1202 cap.
• Ordinary compensation income (phantom gain from ISO disqualifying dispositions, RSU vesting, etc.).

... the timing of the recognition event relative to January 1, 2028 becomes a substantial planning variable. Recognizing these in 2026 or 2027 — before the Washington income tax attaches — can save 9.9% on the incremental dollar above $1M household AGI.

For many founders with a multi-year vest or an anticipated 2028+ exit, this argues for exploring secondary sales in the pre-effective-date window, if deal infrastructure exists.

4. Change domicile before the sale

The most powerful lever, and the most complex. A Washington-resident founder who closes a $50M sale in 2028 faces:

• $0 federal on the first $10M of QSBS gain; 20% + 3.8% on the next $40M of any non-QSBS gain.
• ~$3.1M of Washington 7% capital gains tax on the non-excluded portion.
• ~$4M of Washington 9.9% income tax on the AGI flowing through from the sale (above the $1M threshold).

The same founder who completed a legitimate domicile change to Texas in mid-2027 and closed the same sale in mid-2028 as a Texas resident faces the federal layers only. The Washington capital gains and income taxes fall away.

On a $50M sale with $40M of non-QSBS gain, the Washington tax savings from a successful domicile change approach $7 million. That is the magnitude of planning at stake.

For the mechanics of the move, see How to Leave Washington and the Domicile Planning Checklist.

The "when did you change?" problem

Washington will examine whether you were a Washington resident at the moment the gain was recognized. "Recognized" means different things for different transaction types:

• Stock sale for cash: closing date.
• Stock sale for acquirer stock (§368 reorg): closing date for any cash boot; receipt date for any non-boot shares when later sold.
• Installment sale: each year as payments are received (though taxpayers can elect out under §453(d)).
• Earnouts: when contingencies resolve, unless structured as closed-transaction treatment.
• Escrow holdbacks: when released, generally.

A founder who closes on September 1, 2028 after moving to Texas on January 15, 2028 has eight and a half months of established Texas life at the time of recognition — a defensible position. The same founder closing September 1 after a September 15 move is in trouble before the closing binder is even open.

The recommended sequencing

For a Washington founder with a plausible 2028+ exit on the horizon:

1. 2026 Q4: Confirm §1202 qualification for all tranches of founder stock. If anything is broken, fix it now while there is time.
2. 2027 H1: If domicile change is feasible, make the move. Give yourself at least six months of established new-state life before any closing.
3. 2027 H2: Explore pre-effective-date liquidity — secondary sales, planned disqualifying dispositions, accelerated compensation — for any income that cannot be sheltered under §1202.
4. 2028+: Close the primary transaction. Document the residency story contemporaneously. Assume a 2029–2030 residency audit.

For founders who cannot relocate, the sequencing shifts heavily toward QSBS maximization (including stacking into multiple trusts — see QSBS Stacking Using Trusts) and pre-effective-date acceleration of any non-QSBS income.

Takeaways

• For qualifying §1202 gain within the cap, neither Washington capital gains tax nor ESSB 6346 apply — federal exclusion flows all the way through.
• For non-QSBS gain and for QSBS gain above the cap, both Washington taxes attach — and the combined burden exceeds 16% for 2028+ Washington residents.
• A well-timed domicile change before the sale can eliminate the Washington layer entirely.
• The planning window closes every day. Move the domicile change to the front of 2027 if it is happening.

Full context: ESSB 6346 Complete Guide. Movement playbook: How to Leave Washington.

Last reviewed: April 16, 2026. Nothing in this article is legal or tax advice. §1202 planning is fact-specific and mistakes are often irreversible — consult qualified tax counsel before acting.