Startup tax deadlines for a Delaware C corp: the dated 2027 calendar

A calendar-year Delaware C corporation has 15 dates to hit in 2027

These dates assume a December 31 year end and a company that existed all of 2026. The IRS moves any due date that falls on a Saturday, Sunday or legal holiday to the next business day, which is why January 31, 2027 (a Sunday) becomes February 1, and July 31 and October 31 become August 2 and November 1.

Estimated tax is owed only when the corporation expects $500 or more of tax for the year. A startup with a loss makes no installments, but it still files the return.

A payroll return filed with all deposits made on time gets 10 more calendar days. Other states set their own dates, so check each state where the company has employees, sales or an office.

Payroll and contractor forms are due first, on February 1

The first date of the year is for people you paid. Employees get a Form W-2 and contractors get a Form 1099-NEC, and the IRS copies are due the same day. For payments made in 2026 the 1099-NEC limit is $2,000 per contractor, up from $600 in earlier years.

Late information returns cost $60 each if filed within 30 days, $130 from day 31 through August 1, and $340 after that or if never filed. Those are the amounts for returns due in 2026; the IRS adjusts them each year, so expect slightly higher ones for the returns due in 2027.

Any company that files 10 or more returns of any type in a year, counting payroll and information returns together, must file them electronically. The IRS offers a free portal for this called IRIS. The 1099-NEC guide covers who gets a form.

Delaware's annual report and franchise tax are due March 1, and the default bill is too high

Every Delaware corporation files an annual report and pays franchise tax by March 1. The notice Delaware mails uses the Authorized Shares method, which can come to $85,165 for a startup with 10,000,000 authorized shares. The Assumed Par Value Capital method usually brings it to the $400 minimum. The Delaware franchise tax guide has the worked example.

A Delaware corporation that does business in Delaware also files Delaware's corporate income tax return by April 15, even with no income. A startup that only incorporates in Delaware and operates elsewhere should ask its CPA whether Delaware's return applies.

The federal return is due April 15, even if the company had no revenue

The IRS says all domestic corporations must file an income tax return whether or not they have taxable income. For a calendar year the return, Form 1120, is due the 15th day of the fourth month after year end: April 15, 2027 for 2026.

Form 7004 gives an automatic six months to file, which moves a calendar-year deadline to October 15. It does not extend the time to pay. If you filed an extension for 2025, that return is due October 15, 2026.

• Filing late costs 5% of the unpaid tax for each month or part of a month, up to 25%. For a return more than 60 days late, the minimum is the smaller of the tax due or $525 (the amount for returns due in 2026).
• Paying late costs one half of 1% of the unpaid tax for each month or part of a month, up to 25%, and interest runs even during an extension.
• Missing an estimated tax installment can trigger an underpayment penalty when the tax is $500 or more.

The Form 1120 guide walks through what a no-revenue startup files and what the return records.

The 83(b) election and Form 5472 depend on events, not the calendar

An 83(b) election must reach the IRS no later than 30 days after the date restricted stock is transferred to you. A missed deadline cannot be fixed, so put it on the calendar the day the stock is issued. The 83(b) guide has the steps.

A corporation that is at least 25% foreign-owned and had a reportable transaction with a related party files Form 5472 as an attachment to its return, by the return's due date including extensions. The penalty for failing to file is $25,000 per form, with another $25,000 for each 30 days of continued failure after an IRS notice.

FinCEN no longer requires domestic companies to file beneficial ownership reports

On August 11, 2026 FinCEN issued a final rule that permanently exempts all entities formed in the United States, and their beneficial owners, from reporting beneficial ownership information under the Corporate Transparency Act. It builds on the March 2025 interim rule and takes effect when published in the Federal Register.

Only entities formed under foreign law and registered to do business in a US state still report, and they do not list US persons as owners. A Delaware startup has no BOI deadline and no BOI update duty. FinCEN says it will also delete previously reported information by US persons from its database.

Work backward from each date so nothing is a scramble

1. 1

   Step 1: By January 15: close December, so every category and bank balance is final.

2. 2

   Step 2: By January 20: list every contractor and attorney paid $2,000 or more in 2026, and collect any missing W-9.

3. 3

   Step 3: By January 29: file the W-2s, 1099-NECs and Form 940 so they reach the IRS by February 1.

4. 4

   Step 4: By February 15: read total gross assets off the December 31 balance sheet and issued shares off the cap table for Delaware's annual report.

5. 5

   Step 5: By March 1: file the Delaware annual report and pay the tax.

6. 6

   Step 6: By March 31: give your CPA the closed year, then file Form 1120 or Form 7004 by April 15 and pay the tax you expect to owe.

Each step depends on books that were closed for the year. Dates the company misses usually trace back to a December that was still open in February.