State S-Corp Pitfalls
Washington S-Corp Pitfalls: The B&O Tax an S-Corp Election Can't Touch (2026)
Washington has no income tax, so owners assume an S-Corp election cuts their state tax bill. It does not. The S-Corp saves only federal self-employment tax, while the business and occupation tax and the state capital gains tax sit outside its reach entirely. Here is what the election changes in Washington and what it leaves exactly where it was.
A Seattle marketing consultant books a call with me because her sister in Portland keeps mentioning state tax strategies that do not seem to apply up north. She runs her firm as an LLC, clears about $180,000 a year, and heard that electing S-Corp status would cut her taxes. It will not lower her Washington tax by a dollar, because Washington does not tax her income in the first place. What the election does is cut her federal self-employment tax, and that is worth real money. The consultant is theoretical, but the mix-up is one I see constantly from owners who move to a no-income-tax state and assume the rest of the tax map looks the same.
What an S-Corp election actually does in Washington
Washington has no personal income tax and no corporate income tax, so there is no state income tax for an S-Corp election to reduce. The entire tax benefit of electing S-Corp status in Washington is federal, the self-employment tax you avoid on the distribution portion of your profit. The state savings an S-Corp produces in California or New York do not exist here, because the tax those savings come from was never charged in Washington.
That federal saving is still the main event. Under IRC §1401 and §1402, a sole proprietor pays 15.3% self-employment tax on 92.35% of net earnings up to the Social Security wage base, which the Social Security Administration set at $184,500 for 2026, then 2.9% Medicare tax above it. An S-Corp owner instead pays FICA only on a reasonable salary and takes the remaining profit as distributions free of that tax.
The B&O tax the election cannot touch
Here is the pitfall that catches Washington owners. The business and occupation tax is a tax on gross receipts, and it applies to the business regardless of whether it is a sole proprietorship, an LLC, or an S-Corp. Electing S-Corp status does not lower it, because the B&O tax is charged on what the business takes in, not on its profit, and there is no deduction for the owner's salary or any other cost of doing business. A consultant who paid B&O tax as a sole proprietor pays the same B&O tax after electing S-Corp status.
The Washington Department of Revenue is blunt about the base. There is no deduction from the B&O tax for labor, materials, taxes, or other costs of doing business, and the tax is measured under RCW chapter 82.04 on the full value of what the business receives. The rate depends on your activity. Service and other activities, the classification most consultants and professional firms fall under, is taxed at 1.5% for a business under $1 million in prior-year income, 1.75% from $1 million to just under $5 million, and 2.1% at $5 million and above, a tiered structure that took effect October 1, 2025. Retailing is taxed at 0.471% and wholesaling and manufacturing at 0.484%. Many cities, including Seattle, add their own local B&O tax on top of the state one.
The math, side by side
Here is the consultant's picture. Her firm earns $200,000 of gross receipts and nets $180,000 after expenses. As a sole proprietor she pays self-employment tax on $180,000 times 92.35%, or $166,230, which sits below the wage base, so the full 15.3% applies and the tax is $25,433. As an S-Corp she pays herself a reasonable $100,000 salary, and FICA on that salary is $15,300. Her B&O tax, meanwhile, is 1.5% of the $200,000 she collects, or $3,000, and that does not move when she elects.
What the election changes
Federal self-employment tax
The net federal benefit is a bit lower after the half-SE-tax deduction and QBI. Run your own numbers.
What it leaves untouched
Washington state taxes
Every line in this column reads the same before and after the election.
The federal saving is roughly $10,133 a year, and it is the only column the election moves. The right column is the part owners miss. The B&O tax stays at $3,000 and the state income tax stays at zero, no matter what you do with the entity.
There is no PTET in Washington, and there cannot be
The pass-through entity tax works by paying a state income tax at the entity level and deducting it to get around the IRC §164(b)(6) SALT cap, a structure the IRS blessed in Notice 2020-75. Washington has no income tax, so there is no state income tax to pay at the entity level and nothing to deduct. A Washington owner cannot add a PTET deduction on top of the federal self-employment savings the way an owner in a state with an income tax can.
The capital gains excise tax waits at the exit
Washington does tax one thing that surprises owners who came for the no-income-tax reputation, and the S-Corp election does nothing to shield it. The state imposes a 7% excise tax on long-term capital gains above a standard deduction of $278,000 for 2025, indexed for inflation, under RCW chapter 82.87. A 2.9% surcharge enacted in 2025 raises the top rate to 9.9% on gains over $1 million. Real estate is exempt, and the sale of a qualified family-owned small business can be deductible, but a gain on the sale of a business interest or an investment portfolio above the deduction is taxed whether or not you elected S-Corp status. For an owner planning to sell one day, this is the Washington tax to plan around. The Department of Revenue lists the exemptions in full.
Reasonable compensation still binds
One more trap follows from the no-income-tax setup. Because Washington never taxed the salary-versus-distribution split, some owners treat it as a free lever and set the salary as low as they dare. The same federal standard applies in Washington as everywhere else. You must pay yourself reasonable compensation for the work you do before taking the rest as distributions, and the IRS can reclassify distributions as wages if the salary is too low. In Watson v. Commissioner, 668 F.3d 1008 (8th Cir. 2012), the court upheld the IRS lifting a CPA's $24,000 salary to $91,044. The fact that Washington has no state income tax does not relax the federal reasonable compensation rule at all. Set the salary under IRC §3121 as if the IRS will read your return.
What a Washington S-Corp election does and does not do
So is the election worth it in Washington?
Usually yes, for the same reason it works anywhere. If your profit runs well above a reasonable salary and near the Social Security wage base, the federal self-employment savings on your distributions clear the cost of payroll and an 1120-S many times over. What changes in Washington is that the savings stop at the federal line. There is no state income tax to cut and no PTET to elect, and the B&O and capital gains taxes keep running regardless.
The federal piece still depends on setting a defensible salary. See our guide on S-Corp reasonable compensation and our note on the Social Security wage base, then run the EntityIQ S-Corp tax calculator to put real numbers on your own situation.
This article is educational and is not legal or tax advice. The figures above are 2026 amounts, the Washington capital gains standard deduction cited is the 2025 figure, and the consultant is theoretical. Please consult a qualified CPA or enrolled agent before electing S-Corp status in Washington.