The comparison still matters. The choice affects payroll taxes, income reporting, bookkeeping workload and compliance costs, and for an Australian owner with US activity it adds residency and eligibility questions.
This article covers US rules. Check current IRS and Australian Taxation Office (ATO) guidance before acting. An S Corp is not an automatic tax saver, and the factors below show why.
Key Takeaways
- Self-employment tax is a levy on earnings; an S Corp is a US tax election for eligible entities.
- S Corp owners split income into payroll wages and distributions, but only after paying reasonable compensation.
- Payroll, returns and state costs can cancel out any saving.
- Australian owners face US eligibility, residency and reporting hurdles before an S Corp is possible.
- No universal profit threshold decides the question.
Self-Employment Tax vs S Corp: Quick Comparison
| Factor | Self-employment tax | S Corp |
|---|---|---|
| Nature | A tax on net earnings from self-employment | A federal tax election for an eligible domestic entity |
| Income treatment | Social Security and Medicare tax on net earnings, separate from income tax | Wages go through payroll; allocated income is not self-employment income but remains subject to income tax |
| Owner pay | Owner reports profit, with no W-2 salary | Owner-employee must receive reasonable compensation first |
| Administration | Schedule SE, estimated tax, recordkeeping | Payroll, W-2s, Forms 941/940, Form 1120-S, K-1s, state filings |
| Australian relevance | Mostly governed by Australian rules unless US income, entity or activity creates obligations | Nonresident aliens and corporations cannot be shareholders |
An S election doesn't remove income tax or the employment taxes owed on shareholder wages.
What Is Self-Employment Tax and What Is an S Corp?
What is self-employment tax?
The IRS describes self-employment tax as Social Security and Medicare tax for people who work for themselves. It is separate from income tax. The 2026 rate is 15.3%: 12.4% Social Security (capped at $184,500 of combined covered earnings) plus 2.9% Medicare.
It doesn't apply to every dollar. Schedule SE multiplies net profit by 92.35%, and half the resulting tax is deductible for income tax. An additional 0.9% Medicare tax applies above certain income levels.
A sole proprietorship or single-member LLC is ordinarily disregarded for income tax. Profit flows to the owner's personal return and feeds into this calculation.
What is an S Corp for tax purposes?
An S Corp is not a synonym for an LLC. It is an election, made on Form 2553, by an eligible domestic corporation or LLC. Requirements include:
- No more than 100 shareholders
- One class of stock
- Eligible shareholders only (no nonresident aliens or corporations)
Under the salary-and-distribution model, the owner takes wages through payroll and the rest of the profit passes through as allocated income. The IRS requires reasonable compensation before non-wage distributions.
Relevant factors include:
- Training and experience
- Duties and time commitment
- What comparable businesses pay
When default treatment fits
Default treatment suits a new, low-profit or variable-income business that values simplicity. Compare estimated tax exposure against the cost of formalising an S Corp before switching.
When S Corp taxation fits
An established, US-eligible business with consistent profit well above a defensible salary may benefit. Model the total cost first: payroll, accounting, returns, state requirements and cross-border advice.
Self-Employment Tax vs S Corp: What Is Better?
Compare the whole position, not a single rate. Factor in income tax, payroll or self-employment tax, deductions, benefits and state obligations.
Profit, salary and break-even
Salary assumptions drive the result. A higher defensible salary shrinks the saving. Other wages matter too: Social Security's cap applies to combined earnings, so an owner with large wage income elsewhere may already be over it.
To estimate break-even, subtract these costs from potential payroll-tax savings:
- Payroll service and Form 1120-S preparation
- Bookkeeping and basis records
- Registered agent and state filing fees
- Professional advice
No single profit threshold fits every owner. Anyone quoting a universal break-even figure is guessing.
State costs can bite. California charges 1.5% on S corporation income, with an $800 minimum, and New York City still applies its General Corporation Tax to federal S corporations.
Compliance and risk
Default treatment means Schedule SE and estimated payments. An S Corp adds payroll, a separate return, corporate formalities and basis tracking. A late Form 1120-S costs $255 per shareholder per month (for 2025 returns), up to 12 months.
Misclassifying distributions is the bigger risk. In Watson v. United States (8th Cir. 2012), a CPA paid himself $24,000 while taking over $175,000 in distributions. The court upheld reasonable compensation of $91,044 and the extra employment tax.
Australian owners
Three separate gates apply:
- Eligibility: An Australian company can't hold S Corp shares, and a nonresident alien can't hold them directly.
- Social security: Under the US-Australia agreement, self-employed US citizens residing in Australia are exempt from US coverage. Don't generalise this to every Australian owner.
- Australian classification: A US election doesn't decide Australian treatment. Foreign-hybrid rules, foreign income tax offsets and controlled foreign company rules all apply separately.
Reporting can also apply even without S status. A foreign-owned single-member US LLC with reportable transactions files Form 5472, and the failure-to-file penalty is $25,000.
Situational recommendations
- Default treatment: simpler, and usually right for new or uneven income.
- S Corp modelling: worthwhile for steady profit and a US-eligible owner.
- Specialist advice first: needed whenever Australian residency, an Australian company or cross-border income is involved.
Real-World Examples and Decision Scenarios
The scenarios below stay high-level, except where they cite figures from IRS instructions.
Scenario 1: A new consultancy with uneven income. The owner earns profit in some months and little in others. The goal is low admin and cash flexibility. Payroll every pay period plus an extra return would likely cost more than it saves. Default treatment with quarterly estimated tax is usually the better fit.
Scenario 2: A steadily profitable US-eligible business. The owner works full-time, profit is consistent and the business can sustain a market-level salary. This is where modelling an S Corp makes sense.
Inputs should include salary, other wages, state taxes and compliance fees. The IRS wage example in the Form 8959 instructions shows why: a taxpayer with $220,000 in wages and $20,000 of self-employment income has both counted toward Additional Medicare tax.
The takeaway: the result depends on the owner's facts. Australian businesses with US operations, US entities or cross-border accounting needs can consult VJM Global's tax compliance and accounting professionals for a structured review. The firm has served 250+ Australian businesses and prepares US returns including Form 1120-S, Form 1040 and Form 1040-NR.
Conclusion
Self-employment tax is a tax obligation. An S Corp is a US tax election that may change how owner income splits between wages and distributions. Neither is universally better.
Before electing S Corp status, weigh the full picture:
- Model total tax and compliance costs
- Verify current IRS and ATO rules
- Document reasonable compensation
- Get professional advice
Frequently Asked Questions
What is better, S corp or sole proprietorship?
It depends on profit consistency, potential payroll-tax savings, compliance costs, liability needs and US eligibility. A sole proprietorship is simpler; an S Corp may suit some established US businesses.
Is self-employment tax lower with an S corp?
Possibly. Payroll taxes apply to reasonable wages, while other allocated profit isn't self-employment income. Payroll and compliance costs can offset the benefit.
Do S corp distributions avoid self-employment tax?
Qualifying distributions generally aren't subject to it, but they can't replace reasonable pay. The IRS can reclassify them as wages, and income tax may still apply.
What is a reasonable salary for an S corp owner?
It reflects duties, hours, experience, industry pay and comparable market evidence. The IRS sets no fixed percentage or formula.
Does an LLC automatically become an S corp?
No. An eligible LLC must elect S treatment, generally on Form 2553, and then meet filing and compliance requirements.
Can an Australian business owner use an S corp?
Often not. Nonresident aliens and corporations can't be shareholders, and residency and reporting issues apply. Get both US and Australian advice first.
