Washington's Millionaire Tax: What It Is, What It Costs and What It's Already Doing To Seattle Real Estate

In March 2026, Washington state made history. For the first time in nearly a century, the state passed a personal income tax - a 9.9% levy on household income over $1 million, signed into law by Governor Bob Ferguson on March 30th.

Supporters call it a long-overdue correction to one of the most regressive tax systems in the country. Critics call it the beginning of a wealth exodus that will ultimately cost the state more than it gains. Both arguments have merit. And whether you own property, rent, work in tech, or run a business in the greater Seattle area, this tax is already affecting you. Not in 2028 when it takes effect, but right now, through its impact on property listings, buyer behavior, and the decisions of your neighbors. Here is a plain-language breakdown of what the tax is, who it hits, what the data shows about its real-estate impact, and what both sides of the debate get right.

WHAT IS THE MILLIONAIRE TAX? A PLAIN-LANGUAGE DEFINITION:

Washington’s millionaire tax, officially Senate Bill 6346,  is a 9.9% income tax on annual household earnings above $1 million. It is simple in concept: every dollar your household earns above that threshold is taxed at 9.9% by the state. The first $1 million is untaxed. Washington’s constitution has been interpreted for nearly nine decades as prohibiting a graduated income tax. To work around this, lawmakers framed SB 6346 as an excise tax on the “receipt of income” rather than an income tax itself. That legal maneuver was deliberate and a constitutional challenge was filed almost immediately after the bill was signed. The outcome of that challenge, expected before the tax’s effective date of January 1, 2028, will determine whether the tax ever collects a single dollar.

The rate 9.9% on every dollar of household income above $1 million. Income below $1M is not affected. When it takes effect January 1, 2028. No tax owed before then, even though the law is already signed. First payment due Possibly 2029. The state needs time to build collection infrastructure. Who it affects Roughly 21,000 Washington filers, fewer than 0.5% of the state’s total population. What it funds K–12 school meals, the Working Families Tax Credit, and closing a multi-billion-dollar budget deficit. Real estate sale proceeds Explicitly excluded. Selling your home for $3M does not count toward the $1M income threshold. Legal status Signed into law. Constitutional challenge filed. Could be blocked by courts before 2028. Revenue projection $3.4 billion per year in annual revenue if it survives legal challenge and earners do not leave. The tax does not take effect until 2028 but the real estate market started reacting in February 2026, the day the bill was introduced.

THE 18%, WHERE IT COMES FROM AND WHAT IT ACTUALLY MEANS:

You may have seen the claim that Seattle’s combined top tax rate will reach 18%, the highest of any city in the United States. That number is accurate. But it is not a single tax and it's not the full straightforward picture. It is four separate taxes that land simultaneously on the same high-earning Seattle employee.

The Tax Foundation, a nonpartisan think tank, published this calculation in January 2026: Tax rate notes WA State Millionaire Tax 9.9% On income over $1M. Effective January 2028. Seattle Social Housing Tax 5.0% On compensation over $1M per employee. Active since January 2025. Employer pays, but economists agree the cost ultimately reduces employee wages. Seattle JumpStart Tax 2.557% Applies to large employers with $9M+ in Seattle payroll. City tax only does not apply if you work outside Seattle city limits. WA Cares Long-Term Care 0.58% Statewide on all wages. Funds state long-term care insurance. COMBINED TOTAL 18.037% The highest combined state and local top marginal rate of any jurisdiction in the United States when effective in 2028.

If you work in tech, pay close attention to how you are compensated.

Restricted stock units, RSUs , are how a large share of Seattle tech compensation is structured above the $1 million threshold. When RSUs vest, the IRS treats them as ordinary income in the year they vest, not as capital gains. That distinction is critical under this tax. Capital gains are taxed under a separate Washington framework and face a different, generally lower stack of levies. RSUs that vest as ordinary income, however, are hit by all four layers simultaneously: the 9.9% state millionaire tax, the 5% Seattle Social Housing Tax, the JumpStart tax of up to 2.557%, and the WA Cares tax of 0.58%. This is the specific compensation structure the Tax Foundation was describing when it called the 18.037% rate “eye-popping” and it falls hardest on engineers and executives at pre-IPO companies whose unvested stock can all vest in a single year at a valuation that pushes them far above the threshold. If your compensation is structured as salary plus RSUs which describes the majority of senior tech roles in Seattle and your total household income is approaching or exceeding $1 million, this is a conversation worth having with a tax advisor before 2028. Some employees may have options to defer vesting, negotiate payment structures, or receive a portion of compensation in forms that are taxed differently. None of those strategies eliminate the tax, but they can meaningfully change the year in which the liability falls and whether the $1 million threshold is breached. What the 18% number does not tell you is equally important:

• It applies only to wage income and restricted stock units (RSUs) received from a large employer within Seattle city limits. Most investment income, capital gains, and real estate proceeds face a different and lower tax stack.
• A homeowner living in Mercer Island and working for a Bellevue employer faces roughly 10.5%  not 18%  because the JumpStart and Social Housing taxes are Seattle city levies only.
• About 52% of income earned by Washington’s top earners comes from capital gains and dividends, which are taxed separately and at different rates.
• Founders selling qualified small business stock under federal Section 1202 rules may owe nothing on those gains at the Washington level at all.

WHO IT ACTUALLY AFFECTS:

Fewer than 21,000 Washington residents are projected to owe this tax. To put that in context: Washington has approximately 7.9 million residents. The affected group is less than 0.3% of the population. According to IRS tax data analyzed by Axios Seattle, to be in Washington’s top 1% of earners requires household income of at least $1 million per year, the fifth-highest entry bar for the top 1% of any state in the country. In practice, the people most exposed to this tax are:

• Senior tech executives and engineers at Amazon, Microsoft, and major Eastside firms whose RSU vesting events push annual income over $1M in high-compensation years.
• Startup founders at liquidity events, particularly IPOs, where all restricted stock can vest simultaneously, spiking income dramatically in a single year.
• Small business owners and pass-through entity holders (LLCs, S-corps, sole proprietors) whose business income exceeds the threshold.
• Hedge fund managers, venture capitalists, and investment principals with recurring high-income years.

The tax does not meaningfully affect most Seattle-area homeowners, even those with substantial incomes. A household earning $400,000, well above the regional media, is not a millionaire tax filer. A dual-income household earning a combined $800,000 is also below the threshold. The $1 million mark is a genuine cliff, not a gradual slope.

AT WHAT HOME VALUE DOES THIS TAX BECOME RELEVANT?:

One of the most practical questions for Seattle-area homeowners is this: at what property value does the millionaire tax start to matter? The answer requires mapping income to home prices. At Seattle’s price-to-income ratio of roughly 5x to 6x, higher than the national average of 4.9x, per Harvard’s Joint Center for Housing Studies, a $1 million annual income corresponds most directly to a primary home purchase in the $5M–$6M range. Below that, most buyers are unlikely to be sustained millionaire tax filers.

HOME PRICE RANGE MILLIONAIRE TAX RELEVANCE Under $2 million Unlikely. Typical buyers earn $300K–$500K per year. Tax does not apply unless a one-time RSU vest or business sale spikes income in a single year. $2M – $3.5M Unlikely on a sustained basis. Directors, senior engineers, small business owners. Could breach the threshold in a peak compensation year. $3.5M – $5M Borderline. C-suite, principal engineers, founders post-exit. The most anxious and actively listing segment in the current market. $5M – $8M Likely. Senior executives, fund managers, multi-exit founders. Sustained income above $1M is the norm at this price point. $8M and above Near-certain. These buyers are almost always sustained millionaire tax filers. The most motivated sellers in the current NWMLS data.

THE NWMLS DATA: A PRECISE TIMELINE OF MARKET REACTION:

The Northwest Multiple Listing Service tracks every property listed for sale in the region. When you map the luxury listing data against the legislative calendar, a clear picture emerges. The market did not react slowly. It reacted to specific dates, day by day. The date the NWMLS data shows is that

February 4, 2026 SB 6346 introduced in the state Senate. On that single day, 16 luxury homes priced at $2M or more were listed across Washington, versus 11 on the same date in 2025. A 45% jump on the first day the bill was publicly visible in the legislature.

March 12, 2026 Legislature passes the tax. On that single day, 53 luxury homes were listed statewide versus 32 on

March 12, 2025 - a 65% surge in 24 hours. Howard Schultz announced his move to Miami that same evening.

March 30, 2026 Governor Ferguson signs SB 6346 into law. Statewide active listings are 64% above the long-term March average, per Reventure Consulting’s analysis of NWMLS data. March 2026 (full month) King County: 4,990 active listings, up 34.9% year over year. Eastside inventory up 52.5%. $2M+ King County listings up 84% compared to the same period in 2025. Kirkland listings doubled from 150 to 303.

April 2026 18,563 statewide active listings - up 28.4% year over year and 23.4% from March alone. King County average days to close stretches to 43 days. Closed sales fall 3.4% year over year.

May 2026 (most recent data) 21,381 statewide listings - the highest inventory recorded in 2026. Bellevue west of I-405 posts a median sale price of $4.95M on 13 sales (a thin, volatile sample). Eastside active listings up 24.1% year over year.

The Eastside tells the most concentrated story. Kirkland doubled its listing count. Bellevue and Sammamish surged approximately 70%. Redmond hit 77%. These are not seasonal shifts. They cluster precisely in the zip codes where tech compensation is highest and precisely at the price points where the millionaire tax creates the largest annual liability. +84% King County $2M+ listings, YTD vs. 2025 +102% Kirkland listings year over year +78% $5M+ pending sales, King County

THE CASE FOR WHY SUPPORTERS SAY THIS TAX IS RIGHT:

This is a genuinely contested question, and the strongest arguments on both sides deserve honest presentation. Here is what supporters get right. Washington’s tax structure is genuinely regressive. Without a personal income tax, Washington relies heavily on the sales tax, which takes a proportionally larger share of income from lower-earning households than from wealthy ones. The Institute on Taxation and Economic Policy has consistently ranked Washington among the worst states in the country for tax fairness. The millionaire tax is the most significant attempt in decades to shift that structure. The revenue is real and the need is genuine. Washington’s state operating budget has run a structural deficit for years. The 2025–27 budget faced a $2 billion gap within months of being passed. The projected $3.4 billion in annual revenue from the tax - collected from fewer than 21,000 filers would fund K–12 school meals, expand the Working Families Tax Credit to 460,000 additional households, and begin closing a deficit that has compounded across three consecutive budget cycles. Massachusetts shows the money actually comes in. Massachusetts voters passed a nearly identical 4% surtax on income above $1 million in November 2022. Since taking effect in 2023, it has collected more than $5.7 billion, roughly double the original projections. The number of millionaires in Massachusetts has actually grown 39% since the tax passed. The mass exodus critics predicted there did not materialize at the scale they warned. Forty-one other states already do this. Washington is not testing an untried policy. Forty-one states tax income over $1 million. California has done so since 2004. New Jersey since 2020. New York since 2021. Maine joined in April 2026. The broad national pattern is that most high earners stay because their lives, careers, and networks are built in a specific place, and moving is genuinely disruptive.

THE CASE AGAINST WHY CRITICS SAY IT WILL BACKFIRE:

The opposition to this tax is not simply anti-tax ideology. There are substantive policy arguments worth understanding. Washington’s competitive position is fundamentally different from Massachusetts. When Massachusetts passed its surtax, it already had a personal income tax. High earners there compared their rate to neighboring Connecticut or New York, also high-tax states. A Washington high earner evaluating relocation compares to Nevada and Florida, which have no state income tax whatsoever. Moving from a 14% combined rate to zero is a different calculation than moving from 13% to 10%. The competitive disadvantage Washington creates is more acute than in states where income taxes already existed. At 18%, Seattle becomes a genuine outlier. New York City, previously the highest-taxed jurisdiction in the country for high earners, sits at a combined top rate of 14.8%. Seattle at 18% would be 22% higher than the current national leader. The Tax Foundation’s Jared Walczak, who calculated this figure, called the resulting rate “eye-popping” and noted it would fall disproportionately on tech workers whose RSU vesting drives them above the threshold in peak years, not necessarily the consistently ultra-rich the bill is aimed at. The state may have a spending problem, not a revenue problem. Washington’s state operating budget grew 116% over the past decade, from roughly $80 billion in 2013–15 to $173.5 billion in 2025–27 against 35.6% inflation and 13.8% population growth over the same period. The state has consistently spent more than it collected: $1.9 billion over in 2019–21, $2.6 billion over in 2021–23, $4.1 billion over in 2023–25. Critics argue adding new taxes without addressing structural spending growth simply funds a larger version of the same pattern. The legal challenge may succeed and zero revenue may be collected. Washington’s constitution has been interpreted for nearly a century as prohibiting a graduated income tax. The framing of SB 6346 as an excise tax is legally clever but faces genuine risk. If courts strike it down before January 2028, the projected $3.4 billion in annual revenue disappears. High earners who stayed will have avoided any tax at all. The uncertainty itself is distorting real estate decisions right now.

WHERE PEOPLE ARE GOING AND HOW WE KNOW:

The claim that wealthy Washingtonians are leaving is not speculation. It is documented through three independent and methodologically distinct data sources: federal IRS tax filing records, moving company logistics data, and on-the-ground broker transaction reports from destination markets.

Source 1: IRS Statistics of Income - The Federal Record Every year, the IRS tracks year-to-year address changes on filed tax returns, publishing detailed state-to-state migration data by income level. This is the most authoritative source available on who is actually moving. The most recent full dataset, covering 2022 to 2023, shows that among taxpayers with adjusted gross income of $200,000 or more the highest bracket the IRS tracks the top two destination states nationally were Florida and Texas, both of which have no state income tax. Washington was already experiencing net outflows of high-income filers before the millionaire tax passed. The 2023–2024 and 2024–2025 datasets, when published, will show whether that accelerated after the capital gains tax took effect and as the millionaire tax advanced through the legislature.

Source 2: U-Haul Growth Index - Moving Company Data U-Haul publishes an annual Growth Index based on over 2.5 million one-way truck transactions, ranking states by net migration of customers. Their 2025 data shows Nevada climbed 15 spots to reach number 20 nationally, with 50.4% of all Nevada U-Haul traffic being inbound moves. Critically, a U-Haul study of Henderson, Nevada, one of Las Vegas’s primary suburban markets, identified Washington state as one of the top five origin points for inbound movers, as reported by the Las Vegas Review-Journal. Texas held the number one position nationally on the U-Haul Growth Index, with Dallas-Fort Worth ranking as the top growth metro in the country.

Source 3: Real Estate Broker Reports From Destination Markets In February 2026, the Las Vegas Review-Journal interviewed multiple Nevada brokers and developers about inbound migration. Darin Marques, CEO of Virtue Real Estate and a Henderson-based broker, described a “full-scale migration of wealth” from California and Washington, stating that affluent Washington residents had begun arriving in significant numbers as early as September 2025, months before the millionaire tax bill was voted on, driven by the combination of proposed new taxes and political climate concerns. Realogics Sotheby’s International Realty, which has a Bellevue office, formally launched a “Believing Las Vegas” campaign to connect Eastside clients with Nevada properties, specifically citing the state’s lack of income tax as the primary draw. In Florida, a coalition of three Miami-area real estate developers reported more than $126 million in sales to buyers relocating from high-tax coastal states in just the first 60 days of 2026.

Howard Schultz, former Starbucks chairman and CEO, with a net worth of approximately $3.5 billion, purchased a $44 million penthouse at the Surf Club Four Seasons in Surfside, Florida, and publicly announced his move away from Seattle the same night the state legislature passed the tax. Jeff Bezos relocated from Washington to Florida in 2023 after the state’s capital gains tax passed, reportedly saving at least $610 million on Amazon share sales by avoiding the levy. Marc Barros, CEO of Seattle startup Moment, announced he was relocating his company to Wyoming. Starbucks subsequently announced it would shift 2,000 corporate positions to a new regional headquarters outside Washington state.

DESTINATION WHY AND WHAT THE DATA SHOWS:

Nevada (Las Vegas, Henderson) No state income tax. U-Haul 2025 data names Washington among the top five origin states for Nevada inbound movers. Henderson specifically called out as a high Washington-inflow market. Realogics Sotheby’s launched a formal Bellevue-to-Las-Vegas relocation campaign.

Florida (Miami, South Florida) No state income tax. IRS migration data shows Florida as the top destination nationally for high-income filers. $126M+ in sales from high-tax state buyers in first 60 days of 2026 alone. Howard Schultz, Jeff Bezos among notable Pacific Northwest arrivals.

Texas (Dallas, Austin, Houston) No state income tax. IRS data shows Texas as the top destination state by net filer gain from 2022–2023. Dallas-Fort Worth is the number one U-Haul growth metro nationally. Higher property taxes partially offset income tax savings, but the math still favors Texas significantly for incomes above $1M.

Arizona (Scottsdale, Phoenix) 4.5% flat income tax , far below Seattle’s projected 18% combined rate. Growing tech sector. Lower cost of living than Seattle. IRS data shows Arizona as a significant net gainer of high-income filers from coastal states.

THE MOST IMPORTANT FACT FOR PROPERTY OWNERS:

Real estate sale proceeds are explicitly excluded from the millionaire tax. Under SB 6346, proceeds from the sale of real property, even millions of dollars, do not count toward the $1 million income threshold that triggers the tax. Washington’s existing capital gains tax, in effect since 2022, also explicitly exempts real estate sales. That exemption survived the 2025 rate increase and remains intact. If you sell your home, you are not creating millionaire tax liability from that transaction. The decision of whether to sell, now or later, should be driven by your financial situation, your housing needs, and current market conditions, not by the millionaire tax itself. Where the tax does create real urgency: for high earners who draw substantial W-2 or RSU income and who want to simplify their Washington tax footprint before 2028. That is a specific and different situation from simply owning a Real estate sale proceeds are explicitly excluded from the millionaire tax. Under SB 6346, proceeds from the sale of real property, even millions of dollars, do not count toward the $1 million income threshold that triggers the tax. Washington’s existing capital gains tax, in effect since 2022, also explicitly exempts real estate sales. That exemption survived the 2025 rate increase and remains intact. If you sell your home, you are not creating millionaire tax liability from that transaction. The decision of whether to sell, now or later, should be driven by your financial situation, your housing needs, and current market conditions, not by the millionaire tax itself. Where the tax does create real urgency: for high earners who draw substantial W-2 or RSU income and who want to simplify their Washington tax footprint before 2028. That is a specific and different situation from simply owning a valuable home.

WHAT TO EXPECT THROUGH 2028: Based on the data available as of June 2026, here is an honest read of where this market is likely heading.

• The $3.5M–$8M price band will face the most sustained pressure through 2027 as motivated sellers work to transact before the 2028 effective date. Buyers have more negotiating leverage in this tier than at any point in recent years. Well-priced homes still move. Overpriced listings are sitting 40–60+ days with multiple reductions.
• Prices at the top have not collapsed, but they are softening selectively. The Bellevue west of I-405 median hit $4.95M in May 2026, up 54.7% year over year. But that figure rests on only 13 sales. Thin volume makes medians volatile and unreliable as a trend signal in this tier.
• The Eastside will continue to see more inventory pressure than West Seattle and urban Seattle neighborhoods. Eastside wealth is most directly tied to W-2 and RSU tech compensation, exactly the income type most exposed to the full 18% stack. Kirkland already doubled its listings; that dynamic is not yet resolved.
• If the constitutional challenge succeeds and the tax is blocked before 2028, expect a quick reversal. Sellers who held will re-enter the market, buyers who waited for clarity will compete for the same inventory, and the accumulated supply could clear in a compressed, competitive window, a favorable outcome for sellers who stayed patient.
• If the tax survives legal challenge and takes effect in 2028, the real test comes in 2029, the first payment year. Whether the revenue projections are met, or whether enough high earners have relocated, restructured, or reduced their Washington income to shrink the tax base, will define the next chapter of this story.

Connect with RaeAnne Marcum Real Estate or browse current waterfront listings at www.raeannemarcum.com.