The short version
| Sole proprietor or single-member LLC | S corporation | |
|---|---|---|
| How the owner is paid | Draws; profit is taxed whether or not it is taken out | W-2 salary through payroll, then distributions |
| Federal return for the business | Schedule C with the owner's Form 1040 | Form 1120-S, plus a Schedule K-1 for each shareholder |
| Massachusetts return for the business | Schedule C with Form 1 | Form 355S with Schedule S and an SK-1 for each shareholder; e-file required |
| Owner's Social Security and Medicare | Self-employment tax on net earnings | FICA on the salary only, both halves, through payroll |
| Massachusetts entity-level tax | Income reported on the owner's Form 1 with Schedule C | $456 minimum excise, for every S corporation |
| Massachusetts PFML on owner pay | Optional opt-in for the self-employed | Owner on W-2 is part of the covered workforce, with a family-business exception |
1. Payroll starts, and you are on it
The IRS treats corporate officers who perform services as employees. Fact sheet FS-2008-25 says S corporations should treat payments for services to officers as wages and not as distributions, and the IRS S corporation compensation page says reasonable compensation comes before non-wage distributions. In practice, the election means running payroll for yourself.
That brings the ordinary employer obligations: federal income tax withholding, Social Security and Medicare on the salary, federal unemployment tax on the first $7,000 of wages in 2026, and Massachusetts withholding. Most owners use a payroll provider. Who does which task, the provider, you or your accountant, should be written down before the first pay date, not worked out when a notice arrives.
How much salary is a separate question with no percentage answer. Our page on reasonable compensation covers the factors the IRS lists.
2. Massachusetts registrations
The Department of Revenue says new businesses may need to register through MassTaxConnect for withholding and for Paid Family and Medical Leave. An owner paid through a W-2 is, in the words of the PFML guidance, an employee of the business and part of the covered workforce, unless the business is co-owned by family members; wages of a spouse, minor child or parent are excluded.
Unemployment insurance runs through the Department of Unemployment Assistance, with quarterly wage reports and contributions. Whether an owner-officer's wages are covered is worth confirming with DUA for your situation. If they are, a new employer's 2026 rate is 2.42% on the first $15,000 of each employee's wages, or 6.08% for new construction employers.
- Massachusetts withholding account in MassTaxConnect
- PFML registration and quarterly contributions: 0.88% of eligible wages for 2026, or 0.46% for employers with fewer than 25 covered individuals
- DUA employer account, if the owner's wages are covered
- Corporate excise account for the 355S, if the entity was not already registered for it
The 2027 PFML rate has not been set yet; DFML sets it each year by 1 October. Chapter 101 of the Acts of 2026 also changes how the contribution is split between family and medical leave, which DFML says takes effect 1 January 2027.
3. Your estimated payments change shape
Before the election, all of the business profit sat on your Schedule C and your estimates had to cover income tax and self-employment tax. After it, part of what you take is salary with withholding, and the rest of the profit arrives on a K-1 with nothing withheld.
The IRS says individuals, including S corporation shareholders, generally have to make estimated payments if they expect to owe $1,000 or more when the return is filed. Massachusetts requires estimates when the expected tax not covered by withholding is more than $400. Withholding on the salary covers some of the gap; the K-1 income usually still needs estimates, and the first year is when they are most often miscalculated because last year's return no longer describes how you are paid.
4. Two new returns, and new dates
The corporation files Form 1120-S with the IRS and Form 355S with Massachusetts. The federal return is due on the 15th day of the third month after the tax year ends: for calendar tax year 2026 that is 15 March 2027. For tax year 2025 it was 16 March 2026, because 15 March fell on a Sunday. An extension is requested on Form 7004 before the regular due date.
Massachusetts Form 355S follows the same 15th-day rule, must be filed electronically, and comes with an automatic six-month extension if the payment requirements are met. The corporation owes at least the $456 minimum excise each year. Corporate estimated payments are required only if the excise is reasonably estimated to be more than $1,000, which a small S corporation paying the minimum will not reach.
A late 1120-S carries a penalty of $255 per shareholder per month, up to 12 months, under the 2025 instructions, and $260 for returns required to be filed in 2027.
5. K-1s replace Schedule C
Each shareholder receives a federal Schedule K-1 and a Massachusetts SK-1 showing their share of income, deductions and credits. Your personal return is built from those, so it cannot be finished until the corporation's return is.
Profit on the K-1 is still eligible for the qualified business income deduction, but the salary is not. The IRS says income earned by providing services as an employee is not eligible, so the wages you pay yourself reduce the QBI figure. Any comparison of before and after has to include that.
6. Expenses you pay personally need an accountable plan
As a sole proprietor, a business expense paid from a personal card simply went on Schedule C. As an employee of your own corporation, you are reimbursed. For the reimbursement to stay out of your wages, the arrangement has to meet the accountable plan rules in IRS Publication 463.
Those rules require a business connection, adequate accounting to the employer within a reasonable period, and return of any excess within a reasonable period. Publication 463 treats accounting within 60 days after the expense and returning excess within 120 days as reasonable.
- 1.Adopt a written reimbursement policy for the corporation
- 2.Submit receipts and a short expense report, including business purpose
- 3.Have the corporation reimburse from its own account
- 4.Record the reimbursement as the business expense, not as a distribution
7. Health insurance moves onto the W-2
If you own more than 2% and the corporation pays or reimburses your health premiums, the IRS says it deducts them and includes them in your W-2 Box 1 wages, but not in Boxes 3 and 5, so no Social Security or Medicare tax applies. You may then take an above-the-line deduction under Notice 2008-1, unless you are eligible for a subsidized plan elsewhere.
The payroll provider needs to know about the premiums before the year-end W-2 run. Adding them after the W-2s are issued means corrected forms.
Checklist for the first 90 days
- Confirm the IRS acceptance letter for Form 2553 arrived; follow up if nothing within 2 months
- Open or confirm a business bank account in the corporation's name
- Decide the salary and write down how you reached it
- Choose a payroll provider and agree in writing who handles each filing and deposit
- Register for Massachusetts withholding and PFML in MassTaxConnect; confirm UI coverage with DUA
- Set up an accountable plan for expenses paid personally
- Route health premiums through the corporation if you want the 2% shareholder treatment
- Recalculate federal and Massachusetts estimates for the new pay structure
- Start a basis schedule and set up the books to separate wages, reimbursements and distributions
- Put the 1120-S, 355S and Secretary of the Commonwealth annual report dates in the calendar; check the current annual report fee and due date on sec.state.ma.us
Where we come in
We prepare the 1120-S and 355S, keep the books that feed them, recalculate estimates for the new structure, and offer payroll support alongside your provider, with who does what agreed in writing. If you have not elected yet, we can run the comparison with your actual numbers first. We give you a scope and a price in writing before anything starts.
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.
