The biggest financial disadvantage of a default LLC is self-employment tax — specifically, the 15.3% that applies to 100% of net profit under standard disregarded entity rules. It does not matter how much money you actually withdraw from the business. The IRS taxes the profit — not the paycheck you write yourself.
Taxpayers form an LLC expecting simplicity and liability protection — both valid — without realizing the federal tax treatment quietly creates one of the largest recurring costs in the structure. At meaningful income levels, that cost compounds fast.
How the self-employment tax exposure works
A single-member LLC is treated as a disregarded entity by default. All net profit flows directly to Schedule C on the owner's personal return. The full amount — not just what you pay yourself — is subject to self-employment tax.
That 15.3% breaks down as 12.4% for Social Security — applied up to the 2026 wage base — and 2.9% for Medicare with no cap. Above USD 200k in net income, an additional 0.9% Medicare surtax applies. These are not small line items.
What the numbers look like in practice
Say your single-member LLC generates USD 120k in net profit this year. You only draw USD 60k in cash — the rest stays in the business account for operating expenses. The IRS does not care. The full USD 120k is the self-employment income.
The SE tax on that amount is roughly USD 16,955. That is before federal income tax.
Before state taxes.
Before any entity fees.
The cash you left in the account does not lower what is owed. This is the mechanism that makes the default LLC structure expensive for profitable owner-operators who are actively running the business.
Who pays the most in LLC self-employment tax
Sole proprietors and single-member LLC owners in professional services — consulting, design, coaching, contracting — generally take the hardest hit. Their businesses generate active income, they are the primary service provider, and there are no employees to split the payroll tax burden.
Multi-member LLCs taxed as partnerships face a related but more nuanced version of the same problem. Active members pay SE tax on their distributive share; passive members generally do not. The line between active and passive is not always clean and should not be self-determined without CPA input.
The importance in the context of LLC vs S-Corp Taxes
The self-employment tax exposure under default LLC treatment is precisely why the S-Corp election gets attention. An LLC electing S-Corp status for federal tax purposes requires the owner to take a W-2 salary — but only that salary is subject to FICA payroll taxes. Remaining profit passes through as distributions that may prevent self-employment tax entirely.
That potential gap is real. But so are the costs of creating it. Payroll administration, quarterly filings, Form 1120-S preparation, and state-level franchise taxes in places like California can erode or eliminate the federal savings. The election is not a default upgrade — it is a modeling exercise.
No rule of thumb replaces the actual calculation.
If your LLC is generating consistent net profit above USD 80k –USD 100k, the self-employment tax line on the return is worth examining against the cost of an S-Corp election. Below that threshold, the administrative overhead generally outweighs any tax reduction — though the exact crossover varies with your state, industry, and compensation benchmark.
In order to understand how the self-employment tax disadvantage interacts with the S-Corp election costs in 2026, read the full breakdown at LLC vs S-Corp Taxes 2026 — or contact Wasserman Accounting to model the numbers against your specific return.
