How to use this calendar
Dates here are for calendar-year businesses and owners. A fiscal-year S corporation counts its deadlines from its own year end. Where a due date falls on a weekend or legal holiday, both the IRS and Massachusetts move it to the next business day, which is why some dates below are not the 15th.
Payroll deposit dates depend on your deposit schedule and are not repeated here.
Figures and dates checked on 28 September 2026 against IRS and mass.gov pages. The IRS has not yet published its 2027 filing-season due-date page, and the Department of Revenue has not yet posted 2027 dates, so those rows say expected.
Fourth quarter of 2026
The last months of the year are about the final estimated payment and the extended individual returns for 2025.
| Date | Federal | Massachusetts |
|---|---|---|
| October 15, 2026 | Extended 2025 Form 1040 due (Form 4868 extension) | Extended 2025 Form 1 due |
| October 31, 2026 | Third-quarter unemployment insurance wage report and contributions due to DUA, if you are a covered employer (DUA lists 3 p.m.) | |
| January 15, 2027 | Fourth 2026 estimated tax payment | Fourth 2026 estimated tax payment |
| January 15, 2027 | Fourth 2026 pass-through entity excise estimate, if the entity expects to elect for 2026 | |
| January 31, 2027 | Payment card processors, apps and marketplaces send Form 1099-K copies to payees | Fourth-quarter unemployment insurance report and contributions due to DUA (DUA lists 3 p.m.) |
Information returns: February 1, 2027
Forms 1099-NEC for payments made in 2026 are due February 1, 2027, because January 31 falls on a Sunday. This is the first year the new federal threshold applies: a business generally files a 1099-NEC or 1099-MISC only for payments of $2,000 or more made after December 31, 2025.
Some categories did not move. Gross proceeds paid to an attorney are still reported at $600, and royalties at $10. The threshold is indexed for inflation from 2027 payments.
- Collect a Form W-9 from each contractor before the first payment, not in January
- Total 2026 payments by payee from the books, not from memory
- Check the attorney and royalty categories separately, because their thresholds did not change
- Keep the filing confirmation with the year's records
S corporation season: March 15, 2027
For a calendar-year S corporation, March 15, 2027 carries three deadlines. It is the due date for the 2026 federal Form 1120-S, the 15th day of the third month after year end. It is also the due date for the Massachusetts Form 355S, which follows the same 15th-day-of-the-third-month rule. And it is the last day to file Form 2553 for an S election meant to take effect on January 1, 2027.
A federal extension is requested on Form 7004 before the regular due date. Massachusetts grants an automatic six-month extension for the 355S if its payment requirements are met. An extension of time to file is not an extension of time to pay.
| Item | Federal | Massachusetts |
|---|---|---|
| 2026 S corporation return | Form 1120-S due March 15, 2027 (the 2025 return was due March 16, 2026, because the 15th fell on a Sunday) | Form 355S with Schedule S and an SK-1 for each shareholder, due March 15, 2027; filed electronically |
| Extension | Form 7004, filed before the regular due date | Automatic six months if payment requirements are met |
| Late filing penalty | $260 per shareholder per month, up to 12 months, for returns required to be filed in 2027 | Massachusetts penalties apply separately |
| S election for calendar 2027 | Form 2553 no later than March 15, 2027 | Massachusetts follows the federal S election |
| Pass-through entity excise election | Not applicable | Form 63-ELT, filed electronically with the entity return, if electing for 2026 |
Individual returns: April 2027
Sole proprietors and S corporation shareholders file their individual returns in April. By statute and the calendar, the 2026 federal Form 1040 is expected to be due Thursday, April 15, 2027, but the IRS has not yet published the date. Massachusetts requires a sole proprietor to file Schedule C with Form 1 by the 15th day of the fourth month after the business year ends, which also points to April 15, 2027. Patriots' Day falls on April 19 in 2027, so no shift is expected.
April 15 is also the usual date for the first estimated payment of the new year. The 2027 estimated tax forms have not been released yet, so confirm the dates when they are.
Massachusetts extensions for Form 1 are valid only if at least 80% of the tax is paid by the original due date, based on the DOR's rule for tax year 2025. An extension of time to file is not an extension of time to pay, federally or in Massachusetts.
Estimated tax dates for 2026
Owners with income not subject to withholding generally pay estimated tax four times a year to each government. The federal rule generally applies if you expect to owe $1,000 or more after withholding and credits. Massachusetts generally requires estimates if you expect to owe more than $400 not covered by withholding, and asks you to pay at least 80% of the year's liability during the year.
| Installment | Federal (Form 1040-ES) | Massachusetts (DOR) |
|---|---|---|
| First | April 15, 2026 | April 15, 2026 |
| Second | June 15, 2026 | June 16, 2026 (as printed by DOR) |
| Third | September 15, 2026 | September 15, 2026 |
| Fourth | January 15, 2027 | January 15, 2027 |
An S corporation with only the $456 Massachusetts minimum excise does not make corporate estimated payments; Massachusetts requires them only when the corporate excise is reasonably estimated above $1,000. Pass-through entity excise estimates are separate and are required when the required annual payment is $400 or more.
Payroll and paid leave for owners on W-2
An S corporation owner who takes wages brings the business into Massachusetts payroll obligations. Withholding and Paid Family and Medical Leave are registered through MassTaxConnect, and the Department of Revenue sets your withholding filing frequency when you register.
PFML contributions are reported and paid quarterly. For 2026 the total contribution rate is 0.88% of eligible wages; an employer with fewer than 25 covered individuals sends 0.46%. The 2027 rate has not been set yet; the Department of Family and Medical Leave sets it annually by October 1. Chapter 101 of the Acts of 2026 also changes how contributions are split between family and medical leave, which DFML says takes effect January 1, 2027.
Unemployment insurance reports and contributions are due to the Department of Unemployment Assistance quarterly, by 3 p.m. on April 30, July 31, October 31 and January 31. 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.
- Confirm your withholding filing frequency in MassTaxConnect
- Put the PFML quarterly due dates from your DFML or MassTaxConnect account on the calendar
- Put the DUA quarterly dates on the calendar if you are a covered employer
- Confirm the 2027 PFML rate once DFML publishes it and update payroll before the first 2027 pay date
Annual reports to the Secretary of the Commonwealth
LLCs and corporations registered in Massachusetts file an annual report with the Secretary of the Commonwealth each year. It is a separate obligation from any tax return, and an LLC that elects S corporation status still files it. The due date depends on the type of entity and its formation or fiscal-year dates.
Check the current fee and your due date on the Secretary of the Commonwealth's website, sec.state.ma.us, and put the date on the same calendar as your tax deadlines.
Where we come in
We prepare the returns on this calendar for our clients, work out estimated payments from current books, and can set out which dates apply to your business and who is responsible for each. 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.
