By Isnaini Azizah 
Washington state is currently standing at a fiscal crossroads, poised to abandon its long-held status as one of the few remaining tax-free havens in the United States. For decades, the lack of a state income tax has been a central pillar of Washington’s economic identity, attracting tech giants, aerospace innovators, and high-net-worth individuals to the Pacific Northwest. However, a landmark legislative move is set to change this landscape entirely. The state House of Representatives has officially approved Washington’s first-ever income tax, a 9.9% levy on annual earnings exceeding $1 million. While the bill’s proponents frame it as a necessary tool to combat wealth inequality, tax experts and economists are sounding the alarm over a specific provision that could make Washington’s tax code the most punitive in the nation for married couples: a massive "marriage penalty."
The legislation, which has already cleared the state Senate and is awaiting an almost certain signature from the governor, establishes a 9.9% tax rate on income above the $1 million threshold. While Democratic lawmakers have branded the measure as "the millionaire’s tax," a closer inspection of the statutory language reveals a significant discrepancy in how the threshold is applied. Unlike the federal tax code or the majority of state-level tax systems, Washington’s proposed law does not double the exemption threshold for couples filing jointly. Instead, the $1 million trigger applies equally to individuals, married couples, and domestic partners. This means that two single individuals earning $600,000 each would pay zero state income tax, but if those same two individuals were to marry, their combined $1.2 million income would suddenly subject $200,000 of their earnings to the 9.9% tax.
This structural quirk has led critics to argue that the "millionaire’s tax" is, in practice, a "half-millionaire’s tax" for dual-income households. Joe Wallin, a prominent attorney who advises startups and tech founders in the Seattle area, noted that the statute creates a perverse incentive against legal marriage for high earners. "According to the statute, it doesn’t matter if you’re single or married, the exemption is $1 million," Wallin observed. He went as far as to suggest that for some couples, the tax savings achieved through a legal divorce could easily outweigh the legal fees involved, as the savings on a combined income of $2 million could reach nearly six figures annually.
To understand the magnitude of Washington’s proposal, one must look at how other high-tax states handle similar surtaxes. Marriage penalties are a recurring point of contention in American tax policy, but most jurisdictions attempt to mitigate them by adjusting brackets for joint filers. According to data from the Tax Foundation, a nonpartisan tax policy think tank, most states with progressive income taxes use two separate sets of thresholds. In a typical "neutral" system, the income level at which a higher tax rate kicks in for a married couple is double the level for a single filer.
Even in states known for aggressive taxation of the wealthy, such as New York and California, the marriage penalties are significantly more modest than what is proposed in Washington. In New York, for example, the 9.65% tax rate applies to income above roughly $1.07 million for individuals, but that threshold doubles to $2.15 million for joint filers. New York only begins to eliminate this doubling effect at the extreme high end—specifically for the "super-millionaire" surtaxes of 10.3% and 10.9%, which apply to those making over $5 million and $25 million, respectively. Similarly, California doubles its bracket thresholds for joint filers for almost all of its progressive rates. The only notable exception is the 1% Mental Health Services Act surtax, which applies to all income over $1 million regardless of filing status.
Jared Walczak, a senior fellow at the Tax Foundation, highlights that while New York and California have minor marriage penalties in their top-tier surcharges, the effective rate difference is marginal—usually less than 1%. In Washington, however, the penalty is a staggering 9.9%. "In the most extreme case, if you had two single filers who both earned exactly $1 million, they would owe $0, but if they married and earned the same income, they would owe $99,000," Walczak explained. This disparity makes Washington’s marriage penalty the largest in the country by a wide margin, creating a massive fiscal cliff for high-earning professionals.
The timing of this tax proposal is particularly sensitive given Washington’s economic reliance on the technology sector. The state is home to global powerhouses like Amazon and Microsoft, as well as a burgeoning ecosystem of biotech and cloud computing firms. These industries are characterized by "power couples"—households where both partners may hold senior engineering, legal, or executive roles. In the competitive labor market of the Seattle-Bellevue corridor, dual-income households earning a combined $1.1 million or $1.2 million are not uncommon. Critics like Brian Heywood, a hedge-fund manager and founder of the conservative political action committee Let’s Go Washington, argue that the "millionaire" branding is a populist smokescreen. "There’s this idea that, ‘We’re just taxing rich dudes with yachts,’" Heywood said. "They’ve been less than honest with who they’re going after and what the numbers are."
From a legislative perspective, Democratic leaders have defended the uniform threshold as a matter of administrative simplicity and consistency. State Senator Noel Frame, who oversees fiscal policy for the Senate Democrats, pointed out that the $1 million standard deduction per household mirrors the structure of the state’s capital gains excise tax, which was passed in 2021. Frame argued that maintaining the same deduction across different tax structures helps the Department of Revenue manage the system more efficiently. She also downplayed the impact on the broader population, stating that many high-earning couples would still see a minimal tax impact if their combined income only slightly exceeds the $1 million mark.
However, the "consistency" argument does little to ease fears of capital flight and wealth migration. Washington has historically marketed itself as a low-tax alternative to California, a strategy that has successfully drawn thousands of high-earning residents northward. That competitive advantage is now evaporating. The state has already begun to see high-profile departures following the implementation of the 7% capital gains tax. Jeff Bezos, the founder of Amazon and one of the world’s wealthiest individuals, recently announced his relocation from Seattle to Miami, Florida. While Bezos cited personal reasons for the move, the financial implications are undeniable. By selling more than $9 billion in Amazon stock after his move to Florida—a state with no income or capital gains tax—Bezos effectively saved more than $600 million that would have been owed to Washington state.
Bezos is not an isolated case. Howard Schultz, the former CEO and architect of Starbucks, also announced a move to Miami after 44 years in Seattle. While Schultz stated his foundation would remain in Washington, his personal and family office operations are following him to the Sunshine State. The departure of such "anchor" taxpayers represents a significant risk to Washington’s future revenue stability. If the state’s tax environment becomes perceived as hostile to wealth creation, the very revenue the tax is intended to generate could diminish as the tax base shrinks.
The debate in Washington is a microcosm of a larger national trend. Democratic-led legislatures in states like Rhode Island, Michigan, and Virginia are increasingly exploring wealth and high-earner taxes to fund social programs, healthcare, and infrastructure, especially as federal pandemic-era funding dries up. California is even considering a wealth tax that would target the total net worth of billionaires, regardless of whether they realize income in a given year. Washington’s experiment with a 9.9% income tax and its accompanying marriage penalty will serve as a critical case study for economists. It will test the "elasticity" of high-net-worth residents—determining at what point the cost of living in a specific jurisdiction outweighs the benefits of its cultural and professional ecosystem.
As the governor prepares to sign the bill, the legal community is already bracing for challenges. Washington’s state constitution has historically been interpreted by the courts to prohibit a graduated income tax, treating income as "property" that must be taxed at a uniform rate (not exceeding 1%). The 2021 capital gains tax survived a legal challenge only because the state Supreme Court classified it as an "excise tax" on the sale of assets rather than an income tax. Proponents of the new 9.9% levy are likely to use similar legal gymnastics, but the inclusion of a significant marriage penalty adds a new layer of potential constitutional and civil challenges regarding equal protection and the fundamental right to marriage.
For the dual-income households of the Silicon Forest, the future remains uncertain. If the law takes effect as planned, Washington will transition from a tax-friendly frontier to one of the most expensive states for high-earning couples in America. The shift represents a fundamental gamble by state leaders: that the allure of Washington’s natural beauty and its dominant tech industry is strong enough to keep the wealthy from packing their bags for Florida, Texas, or Nevada. Whether that gamble pays off, or whether it triggers a "Great Migration" of capital, will likely shape the state’s economic trajectory for the next generation.