How the S-Corp Tax Structure Works
An S-corporation is a tax election available to LLCs and traditional corporations. The legal entity remains an LLC or C-corp, but for tax purposes the IRS treats it as an S-corp — passing income through to owners (avoiding C-corp double taxation) while distinguishing wages from distributions.
As a sole proprietor or LLC member taxed as a sole proprietor, your entire net business income is subject to self-employment tax (15.3% on 92.35% of net income, capped at the SS wage base of $184,500 for the 12.4% SS portion in 2026; Medicare at 2.9% has no cap).
As an S-corp, you split your income into two pieces: a W-2 wage from the corporation to yourself (subject to 15.3% combined FICA) and a K-1 distribution of remaining profits (subject to ordinary income tax but NOT SE tax or FICA). The savings come from the FICA-exempt distribution portion.
Concrete example: $200,000 of net business income. As sole proprietor: SE tax is $24,300. As S-corp paying yourself $100,000 W-2 wage and $100,000 distribution: FICA on wages $15,300 + zero on distribution = $15,300. Savings: $9,000. Minus S-corp overhead (payroll, accounting, state filings) of roughly $2,500. Net savings: $6,500/year.
When the Math Actually Works
Below ~$80,000 of net business income, the S-corp election typically doesn't pay off. The savings on $30,000-$50,000 of distributions (which is what's left after a reasonable salary at this income level) are about $4,500-$7,500 — barely enough to cover the $2,000-$3,000 of additional accounting and payroll overhead.
Sweet spot: $100,000-$300,000 of net business income. At $150,000 with a $60,000 reasonable salary: $90,000 of distributions × 15.3% = $13,770 of SE tax savings, minus $3,000 overhead = $10,770 net. Clearly worthwhile.
At $300,000+, the SS portion of FICA stops at $184,500 (the 2026 wage base), so additional distributions only save 2.9% Medicare (plus 0.9% additional Medicare for high earners). Still worth it but the savings rate decreases above the SS cap.
QBI deduction interaction: the Qualified Business Income deduction (Section 199A) is available to S-corps. But for Specified Service Trades or Businesses (SSTBs — consulting, law, financial services, etc.) above $200K single / $400K MFJ, the QBI phases out. S-corp wages can affect the phase-out calculations in complex ways. Run the full math with a tax pro at higher income levels.
Reasonable Salary: The IRS Scrutiny Point
The IRS requires S-corp owners to pay themselves 'reasonable compensation' before taking distributions. Setting a $20,000 salary on $250,000 of profit invites audit and reclassification — the IRS will recharacterize distributions as wages and assess back FICA plus penalties.
What's 'reasonable'? The IRS looks at: industry surveys (BLS, Robert Half), what you'd charge a third party for similar work, your experience and credentials, hours worked, and the company's profitability. There's no bright-line rule, but court cases have provided guidance.
Practical benchmarks: software developers $100K-$180K, marketing consultants $80K-$140K, freelance writers $60K-$100K, financial advisors $80K-$150K, dentists $150K-$300K. Adjust by location, experience, and specialty.
Documentation matters. Keep records of your reasoning: industry survey citations, comparable W-2 jobs you've held or seen, hours worked, and the corporation's profitability. If audited, you need to defend the salary determination as reasonable.
Common defensible ratio: a salary of 30-50% of net business income is typically defensible for service businesses. So $200K of profit might support a $60K-$100K salary. But this is a rough heuristic — the IRS examines actual facts and circumstances.
Setup and Ongoing Operational Requirements
Initial setup: form an LLC or corporation in your state ($100-$500 in filing fees, plus $200-$1,500 for an attorney if you use one). File Form 2553 with the IRS to elect S-corp tax treatment (must be filed by March 15 for the current tax year, or for newly formed entities within 75 days of formation).
Payroll setup: you must run payroll on yourself, paying W-2 wages with proper withholding. Use a payroll service (Gusto, ADP, OnPay) — typically $40-$80/month. The service handles federal and state withholding, files quarterly Form 941, generates W-2 at year-end, and pays unemployment insurance.
Annual tax returns: S-corps file Form 1120-S federally (separate from your personal 1040). You receive K-1 reporting your share of the income. Most CPAs charge $1,500-$3,500 for S-corp returns plus your personal return.
State considerations: most states recognize S-corp elections, but some impose franchise taxes or annual fees regardless of profitability (California's $800 minimum franchise tax is the most common gotcha). Some states (NJ, NY, TN) require separate state-level S-corp elections.
Quarterly estimated taxes still apply. Even though you're paying yourself W-2 wages with withholding, the K-1 distribution income isn't withheld — you need to make quarterly estimated payments on your share of pass-through income.
Tax Pitfalls to Avoid
Unreasonably low salary: discussed above. The biggest mistake new S-corp owners make. Set a defensible salary backed by industry data and stick to it.
Skipping payroll. Some new S-corp owners 'just take distributions' without running payroll. The IRS treats this as a complete failure to comply with reasonable compensation requirements — likely reclassifying ALL distributions as wages and assessing back FICA.
Mixing personal and business expenses. S-corps require strict separation between personal and corporate funds. Use separate bank accounts and credit cards. Don't pay personal expenses from the business — and don't pay business expenses from personal accounts (without proper reimbursement).
Forgetting state-level filings. Annual reports, franchise tax filings, and state-specific tax returns are easy to forget. Many S-corp owners get hit with late fees, automatic dissolution notices, or state tax assessments because they forgot a $50 annual report.
Not adjusting for income changes. If your business income drops significantly, your S-corp might not have enough income to support your salary. You may need to reduce your salary (with documentation of the reasoning) or eat the FICA cost on the salary even though distributions are zero. Conversely, if income surges, you may need to increase salary to maintain a defensible ratio.
When NOT to Use S-Corp
Below $80K of business income: overhead exceeds savings, often by enough that you net nothing.
Volatile or unpredictable income: if your income swings between $40K and $200K depending on the year, the S-corp overhead is fixed but the savings only apply in high-income years. Sole prop or LLC sole-prop tax treatment is more flexible.
Single member, low complexity: if you're a single freelancer with simple tax structure, the operational burden of running payroll, separate tax filings, and state compliance may not be worth the savings even at moderate income levels. The simplification value of remaining a sole proprietor has real cost benefit.
Real estate investing: rental income is generally exempt from SE tax, so the S-corp election doesn't help. Real estate operators (active flipping, development) might benefit, but passive landlords get no SE tax advantage from S-corp.
Owners of multiple businesses: if you have several income streams flowing through different LLCs or sole props, structuring all of them as S-corps creates massive complexity. Consider consolidating under one S-corp or accepting some SE tax cost on smaller streams.
International situations: S-corps cannot have non-US shareholders. If you have a foreign business partner or plan to relocate abroad, S-corp may not be the right structure.