The two paths in one table
| Sole proprietor or single-member LLC | S corporation | |
|---|---|---|
| Federal return | Schedule C and Schedule SE with Form 1040 | Form 1120-S and a K-1, plus your Form 1040 |
| Massachusetts return | Schedule C with Form 1, due the 15th day of the fourth month after the business year ends | Form 355S with Schedule S and SK-1s, due the 15th day of the third month, plus your Form 1 |
| Employment tax on the owner | 15.3% self-employment tax on 92.35% of net earnings; Social Security part capped at $176,100 (2025) or $184,500 (2026) | FICA of 15.3% on the salary only, split between the business and you, with the same cap |
| Profit above the salary | Subject to self-employment tax | Passes through as income without employment tax |
| Federal QBI deduction | Based on profit less the deductible half of self-employment tax and some other items | Based on profit after salary and the employer's FICA; the salary is not QBI |
| Massachusetts entity tax | None | At least $456 each year; more only at $6 million or more of total receipts |
| PFML | Optional; a self-employed person may opt in, paying 0.88% (2025 and 2026) and staying enrolled for 3 years | The owner's W-2 wages are part of the covered workforce, unless a family-owned exception applies |
| Unemployment insurance | Not on the owner | Confirm with DUA; if covered, 2.42% on the first $15,000 for a new employer in 2026 |
| Payroll | None for the owner | Required: withholding, deposits, employment returns and a W-2 |
| Estimated tax | Federal estimates and Massachusetts estimates if expected tax due exceeds $400 | Withholding from salary covers part; distributions may still need estimates |
| Secretary of the Commonwealth | LLC annual report if you have an LLC; none for an unincorporated sole proprietorship | Annual report for the LLC or corporation; check the current fee on sec.state.ma.us |
Illustrative: the same $120,000 profit, two ways
Round numbers for tax year 2026, single owner, no other household wages, fewer than 25 covered individuals. The S corporation salary of $60,000 is an assumption for the example, not a suggestion of what is reasonable for any job.
As a sole proprietor, self-employment tax is $120,000 × 92.35% × 15.3%, which is about $16,955. As an S corporation, FICA on a $60,000 salary is $9,180, half paid by the business and half withheld from the owner. The employment tax difference is about $7,775.
| Line | Sole proprietor | S corporation |
|---|---|---|
| Employment tax on the owner | $16,955 | $9,180 |
| Massachusetts minimum excise | $0 | $456 |
| PFML at 0.46% of $60,000 | $0 | $276 |
| UI at 2.42% of $15,000, if DUA treats the wages as covered | $0 | $363 |
| Approximate QBI deduction at 20%, assuming no other limit applies | $22,305 | $11,082 |
| Payroll provider, extra return preparation, FUTA | Not applicable | Your own figures |
The S corporation's QBI deduction is roughly $11,200 smaller in this example, which at an illustrative 22% federal bracket is about $2,470 of added federal income tax. After the excise, PFML and UI, that leaves roughly $4,200 of the $7,775 before payroll and preparation fees. None of this is a projection for any business.
Massachusetts personal income tax is broadly the same either way
For Massachusetts personal income tax, the owner's business income ends up on Form 1 on both paths: as Schedule C profit for a sole proprietor, and as wages plus the SK-1 share for an S corporation owner. The rate on most of that income is 5.00%. The Massachusetts difference between the two paths is therefore mostly the new costs: the excise, PFML, possibly UI and the extra return.
Two Massachusetts items can tilt things toward an S corporation for particular owners. Only S corporations and partnerships can elect the Chapter 63D pass-through entity excise, which can help owners whose state taxes exceed the federal SALT cap. And for owners near the 4% surtax threshold ($1,083,150 for 2025, $1,107,750 for 2026), the new Chapter 63E excise is available from tax year 2026.
Who usually does better staying a sole proprietor
These patterns are not rules, but they come up often when the lines are laid out.
- Profit that is small relative to the fixed costs: the $456 minimum, payroll fees and extra preparation arrive every year regardless.
- Irregular profit, where a slow year would leave too little to pay a reasonable salary.
- Businesses expecting losses, especially early on, where S corporation basis rules can limit how losses are used.
- Owners whose profit comes almost entirely from their own services, so a reasonable salary sits close to the whole profit.
- Households where other W-2 wages already reach the Social Security wage base, so less self-employment tax is at stake.
- Owners who do not want to run payroll or keep the tighter books an S corporation needs.
Who tends to benefit from an S corporation
The owners who tend to come out ahead have steady profit comfortably above what a reasonable salary for their work would be, books that are already reconciled monthly, and the willingness to run payroll properly. Businesses where a meaningful share of receipts comes from staff or equipment rather than the owner's own hands often fit this profile.
Even then, the size of the benefit depends on the QBI effect and the real cost of payroll and preparation, which is why the comparison has to be run with actual figures.
Where we come in
We can run the comparison with your actual numbers: your profit from reconciled books, a salary you can support, your household's other income and every Massachusetts line in the tables above. If staying a sole proprietor is the better answer, we will say so. We give you a scope and a price in writing before anything starts.
Before deciding, it is worth reading what an honest comparison must include, so you can judge any estimate you are shown.
Figures on this page were checked against the IRS and Massachusetts sources listed alongside on 28 Sep 2026. They change — confirm the current amount before relying on one.
General information for owner-led businesses, not advice for your specific situation. Tax and accounting rules change, and how they apply depends on facts particular to your business. Talk to us — or to another qualified professional — before acting on anything here.
