Washington's Capital Gains Tax (Now Up to 9.9%): Residency Planning Before You Sell

Key Takeaways

• Washington's capital gains tax can reach 9.9% on gains above $1M.
• Domicile, not day count alone, determines tax liability at sale.
• Moving before LOI strengthens evidence of genuine domicile change.
• Maintain <183 Washington days and no Washington abode to avoid residency.
• QSBS exclusion can eliminate need for relocation if fully applicable.

Pulse Analysis

Washington’s 2024‑25 capital‑gains excise tax marks a sharp shift for tech founders who have traditionally benefited from the state’s lack of income tax. By taxing long‑term gains at 7% up to $1 million and 9.9% beyond, the measure can erode multi‑million‑dollar exits, prompting founders to treat residency as a strategic lever rather than a peripheral concern. Unlike ordinary income taxes, the Washington tax hinges on the seller’s domicile at the moment of sale, not merely on where they spend the majority of the year, which forces a deeper dive into personal and family ties, property ownership, and day‑to‑day habits.

The practical path to avoidance centers on establishing a new domicile before the closing date. Early relocation—ideally before a letter of intent—is critical because it creates a contemporaneous record that is harder for the Department of Revenue to dispute. Founders must align driver’s licenses, voter registration, banking relationships, and even medical providers with the new state, while simultaneously reducing Washington‑based days below the 183‑day threshold. Auditors scrutinize granular evidence such as credit‑card locations, cell‑tower data, and calendar entries, so meticulous documentation is essential. A partial move, where the family or primary residence remains in Washington, typically fails the “substantial evidence” test and can trigger a costly audit.

Coordinating the Washington analysis with federal tax strategies amplifies savings. Section 1202 qualified small‑business stock (QSBS) exclusions can offset a substantial portion of the gain, often removing the need for a domicile shift when the exclusion fully covers the proceeds. However, when QSBS only partially shelters the gain, a combined approach—leveraging both the exclusion and a bona‑fide move—offers the most robust protection. Founders should also consider the timing of earn‑outs, installment payments, and rollover equity, as each stream may be subject to separate domicile analysis. In sum, proactive residency planning, backed by solid evidence and aligned with federal tax tools, is now a non‑negotiable component of any high‑value exit strategy in Washington.