
Taking effect for the first time this year, Washington is now the only state in the country to impose a standalone income tax on capital gains
Jason Mercier
Mountain States Policy Center
With property tax assessments increasing rapidly in Wyoming, some have begun to discuss whether there should be changes to the Cowboy State’s tax structure. It is important to first remember that assessed property values do not necessarily drive the actual property tax bill. Instead, that tax obligation is primarily set through the budget process by the amount to be spent (whether approved by government officials or voters through levies).

Concerning Wyoming’s current tax structure, as one of just a handful of states without a personal income tax, extreme caution should be taken to avoid losing this economic competitive advantage. This is especially true with any discussion of imposing a highly volatile and unpredictable income tax on capital gains.
Taking effect for the first time this year, Washington is now the only state in the country to impose a standalone income tax on capital gains (other income tax states tax it as ordinary income as part of their income tax codes). The policy choice has resulted in national tax rankings removing Washington’s prior standing of not having a personal income tax.

The federal Internal Revenue Service (IRS) has made it very clear that a capital gains tax is an income tax. Our friends at the Washington Policy Center posted this letter from the IRS clearly explaining this fact.
IRS: “This is in response to your inquiry regarding the tax treatment of capital gains. You ask whether tax on capital gains is considered an excise tax or an income tax? It is an income tax. More specifically, capital gains are treated as income under the tax code and taxed as such.”
Imposing taxes on capital gains income is not a recipe for predictable state revenue.
As explained by the California Legislative Analyst’s Office (LAO):
“California’s tax revenues have numerous volatile elements, but among the more significant sources of revenue volatility are the state’s tax levies on net capital gains through the personal income tax.”
“Capital gains depend heavily on movements in financial markets. As such, capital gains revenue is extremely volatile and difficult to predict. In any given year, there is significant risk that capital gains revenue could fall below budgetary expectations.”
If the goal of structural state tax reform is to improve budget stability and avoid boom-and-bust tax collections, an income tax on capital gains is the worst possible choice Wyoming policymakers can make.
Jason Mercier is the vice president and director of research at the Mountain States Policy Center.
Also read:
- Opinion: Washington’s fight for libertyConservative columnist Nancy Churchill argues that despite the passage of a new 9.9% state income tax, signs of shifting political momentum in Washington state give reason for hope and continued action.
- Opinion: Brandi Kruse and I are feeling discouraged but we’re planning to continue advocating for political change. Will you?Clark County Today Editor Ken Vance reflects on a discouraging week in Washington state politics, echoing Brandi Kruse’s frustrations over Democrats’ state income tax victory and local decisions on transit and ICE while urging conservatives not to give up on advocating for political change.
- Opinion: ‘My thoughts on yesterday’s tragic state income tax’Leslie Lewallen argues Democrats passed an unconstitutional “millionaires tax” on March 10, 2026, rejected more than 70 Republican amendments, and set Washington on a path she says will harm jobs, schools, and families statewide.
- Opinion: Starbucks founder flees the new NW tax hellLars Larson argues that Howard and Sheri Schultz are leaving the Pacific Northwest for Miami following Washington’s new millionaires tax and rapid state budget growth in Oregon and Washington.
- Letter: ‘One year later, a withheld text message points to perjury’Clark County resident Rob Anderson argues a previously undisclosed text message tied to a C-TRAN board dispute raises questions about sworn statements and public meeting rules.







