Form 1120 is the annual US Corporation Income Tax Return that every Delaware (and other US) C-Corp must file with the IRS, due on the 15th day of the 4th month after the corporation's tax year ends — April 15 for a calendar-year company. The C-Corp pays a flat 21% federal tax on its profits on that return, and you can push the filing deadline (not the payment deadline) six months with Form 7004. You can file it from anywhere in the world; you do not need to be in the US, and a foreign owner files the same Form 1120 as a US owner — just with an extra information return attached.
Who files: every US C-Corp files Form 1120 every year, even with $0 of income or activity.
Deadline: 15th day of the 4th month after year-end — April 15 for calendar-year corps; Form 7004 buys a 6-month extension to file.
Tax: 21% flat federal rate on corporate profits; the extension extends filing, never payment.
Late-file penalty: 5% of unpaid tax per month, up to 25%. Late-pay penalty: 0.5% per month, up to 25%.
Foreign owners: a 25%+ foreign-owned C-Corp also attaches Form 5472 — missing it is a flat $25,000 penalty.
When is Form 1120 due for a C-Corp?
Form 1120 is due on the 15th day of the 4th month after your corporation's tax year ends.
Most C-Corps use a calendar tax year ending December 31, which puts the deadline at April 15. If you adopt a fiscal year — say, one ending June 30 — your due date shifts accordingly, and the IRS keeps an authoritative chart in Publication 509, Tax Calendars. The form itself, the instructions, and the e-file path all live on the IRS About Form 1120 page.
Need more time? You get six months automatically — but read the next sentence carefully.
Filing Form 7004 by the original due date gives you an automatic 6-month extension to *file* the return — moving a calendar-year deadline from April 15 to October 15. Form 7004 extends the time to file, never the time to pay: any tax owed is still due on the original April 15 date, and interest plus the late-payment penalty start accruing the day after.
What does a C-Corp actually owe on Form 1120?
A C-Corp pays a flat 21% federal income tax on its taxable profits, reported on Form 1120.
There is no graduated bracket and no minimum income threshold to file — a profitable corporation computes 21% of its taxable income, and a corporation with no profit still files a return showing zero. Unlike a single-member LLC, a C-Corp is a separate taxpayer, so its income does not flow to your personal return; it is taxed at the entity level first.
That entity-level tax is also why founders talk about "double taxation."
If the corporation later distributes profits as dividends, those can be taxed a second time at the shareholder level. This is the classic trade-off behind choosing a C-Corp over a pass-through structure — worth weighing before you incorporate, which the Wyoming LLC vs Delaware C-Corp guide breaks down for non-resident founders.
What are the penalties for filing Form 1120 late?
Two separate penalties can hit at once: one for filing late, one for paying late.
The failure-to-file penalty is 5% of the unpaid tax for each month (or part of a month) the return is late, capped at 25%. The separate failure-to-pay penalty is 0.5% of the unpaid tax per month, also capped at 25%, and it keeps running until the tax is paid. When both apply in the same month, the IRS reduces the 5% file penalty by the 0.5% pay penalty, per the IRS Failure to File Penalty guidance.
There is also a floor penalty that catches even a $0-tax return filed very late.
As of 2026, if your return is more than 60 days late, the minimum failure-to-file penalty is the smaller of the tax due or $525 (this figure is indexed and rises over time). On top of the penalties, the IRS charges interest on unpaid tax from the original due date — so an extension to October does not stop the meter on money you owe.
| Item | Detail | Penalty if you miss it |
|---|---|---|
| File Form 1120 | April 15 (15th day, 4th month) | 5% of unpaid tax/month, max 25% |
| Pay tax owed | April 15 (extension does NOT move this) | 0.5% of unpaid tax/month, max 25% + interest |
| Extension (Form 7004) | Filed by April 15 → file by Oct 15 | No extension penalty; payment still due Apr 15 |
| Return >60 days late | Minimum penalty applies | Smaller of tax due or $525 (2026) |
| Form 5472 (if 25%+ foreign-owned) | Attached to Form 1120, same deadline | $25,000 per form |
How does a non-resident founder file Form 1120 from abroad?
You file the exact same Form 1120 from abroad — being a foreign owner does not change the corporate return itself.
What changes is what you attach. A US C-Corp that is at least 25% foreign-owned must also file Form 5472, an information return that discloses transactions between the corporation and its foreign owner. This is the trap that costs non-resident founders the most: the Form 5472 penalty is a flat $25,000 per form, and it applies even if the corporation made no money and had nothing to report.
Most C-Corps can e-file Form 1120 and Form 7004 from any country, and you pay any tax due electronically to the IRS in USD. You do not need a US address or to set foot in the country to file — but you do need an EIN and clean books that tie out to your bank and payment records, because Form 5472 specifically asks for reportable transactions with the foreign owner.
This article is general information, not legal or tax advice; corporate filings are time-sensitive, so confirm current deadlines and penalty figures at irs.gov or with a CPA before you file.
The Form 1120 detail most guides miss: clean USDC records make the return trivial
The hard part of Form 1120 for a remote founder is rarely the math — it is reconstructing what money moved, especially when revenue arrives as stablecoin across multiple chains.
A C-Corp that invoices in USD but settles in USDC or USDT on Solana, Ethereum, or Polygon has to convert every on-chain receipt and off-ramp into clean USD figures for the return — and a DIY direct-wallet path leaves you with a tangle of transactions and no paper trail when the IRS (or a Form 5472 line) asks what happened.
StableCorp runs the off-ramp on compliant rails with a proper paper trail, so the numbers that land on Form 1120 and Form 5472 are already reconciled — not pieced together from block explorers the night before April 15.
For clients incorporated with StableCorp, the off-ramp is 0.5% and the on-ramp is 1.5%, versus the market's roughly 2.9% headline plus about 2% hidden FX markup that lands near 5% effective — and Indian founders can off-ramp directly to INR at 1% on RBI purpose-code rails. Cleaner records and a lower payout cost on the same return: see pricing for the full schedule.
Form 1120 vs Form 5472: which does your entity file?
It depends on whether you run a C-Corp or a foreign-owned single-member LLC — they file different returns.
A C-Corp files a full Form 1120 and pays 21% on profits; if it is 25%+ foreign-owned, it attaches Form 5472. A foreign-owned single-member LLC, by contrast, is a disregarded entity — it files Form 5472 with a pro forma (mostly blank) Form 1120 as a cover, every year even with zero activity, and it cannot e-file that package. The foreign-owned US LLC explained guide covers that filing in detail.
Pick the wrong mental model and you file the wrong return.
StableCorp forms both Wyoming LLCs and Delaware C-Corps, gets your EIN, opens the US bank account, and can onboard an existing entity — so the right return is mapped to your structure from day one. Start with pricing to see the all-in cost.
Sources
IRS — About Form 1120, U.S. Corporation Income Tax Return — https://www.irs.gov/forms-pubs/about-form-1120
IRS — Instructions for Form 1120 (2025) — https://www.irs.gov/instructions/i1120
IRS — Instructions for Form 7004 (Automatic Extension) — https://www.irs.gov/instructions/i7004
IRS — Failure to File Penalty — https://www.irs.gov/payments/failure-to-file-penalty
IRS — Publication 509, Tax Calendars — https://www.irs.gov/publications/p509
IRS — About Form 5472 — https://www.irs.gov/forms-pubs/about-form-5472