The costliest US tax-filing mistakes foreign founders make are skipping Form 5472 on a foreign-owned LLC, filing Form 1120 late, and forgetting state franchise tax or the annual report. The first one alone carries a flat $25,000 penalty — and it applies even if your company earned $0 and did nothing all year. None of these are about how much tax you owe; they are about paperwork the IRS and your state of formation expect on a fixed date, whether or not you made money.
Missed Form 5472 (foreign-owned single-member LLC): flat $25,000 per form — owed even with zero income or activity.
Late Form 1120: 5% of unpaid tax per month (max 25%) to file late, plus 0.5%/month (max 25%) to pay late, plus interest.
Missed Delaware franchise tax / annual report: $200 penalty + 1.5% interest per month; the corporation loses good standing.
Missed Wyoming annual report: entity faces administrative dissolution if unpaid 60 days past the due date.
The trap: every one of these is due annually even at $0 revenue — being inactive does not excuse the filing.
Why does a Form 5472 mistake cost $25,000?
Because Form 5472 is an information return, the penalty is flat — it does not scale with your income, so a dormant company is exposed to the same $25,000 as a profitable one.
A US LLC with a single foreign owner is treated as a "disregarded entity" for tax — but since 2017 the IRS still requires it to file Form 5472 attached to a pro forma (mostly blank) Form 1120, reporting transactions between the LLC and its foreign owner. Capital you contributed to start the company, money you moved between yourself and the LLC, and the formation costs all count as reportable transactions. Miss it, file it late, or file it incomplete, and the penalty is a flat $25,000 per form, per the IRS Instructions for Form 5472.
The deadline is the part founders trip on most.
The 5472 package is due April 15 for a calendar-year LLC, and you can push that to October 15 with Form 7004 — but unlike most IRS returns, this package cannot be e-filed. You fax or mail it, which means a last-minute filing has no instant confirmation. If you run a foreign-owned LLC, walk through the mechanics in the foreign-owned US LLC explained guide before your first April 15.
What happens if you file Form 1120 late?
Two separate penalties can stack: one for filing late and one for paying late.
A US C-Corp files Form 1120 and pays a flat 21% federal tax on its profits, due on the 15th day of the 4th month after year-end (April 15 for calendar-year companies). File late and the failure-to-file penalty is 5% of the unpaid tax per month, capped at 25%; pay late and the failure-to-pay penalty is 0.5% per month, also capped at 25%, with interest running on top — both detailed on the IRS Failure to File Penalty page.
The mistake that quietly costs the most is misreading what an extension buys you.
Form 7004 extends the time to *file* by six months — it never extends the time to *pay*. Any tax owed is still due on the original April 15 date, and interest plus the late-payment penalty start the day after, even if your return is not due until October. Founders who file a clean extension and assume they are covered are often surprised by an interest bill months later.
Which state filing do non-resident founders forget?
The state annual report and franchise tax — because they are owed to your state of formation, not the IRS, and they run on a completely different calendar.
Founders watch April 15 and forget that Delaware and Wyoming have their own deadlines. A Delaware corporation's franchise tax and annual report are due March 1 every year; miss it and the state adds a $200 penalty plus 1.5% interest per month and the corporation falls out of good standing, per the Delaware Division of Corporations Annual Report and Tax Instructions. A Delaware LLC instead owes a flat $300 annual tax due June 1, with the same $200-plus-interest penalty.
Wyoming runs on yet another clock.
A Wyoming LLC's annual report is due the first day of its anniversary month — the month you originally formed — with a license tax of $60 minimum, per the Wyoming Secretary of State. Leave it unpaid for 60 days past the due date and the state can administratively dissolve the entity, which quietly breaks your bank account and contracts. The mechanics of staying current are in the annual reports and good standing guide.
| Filing | Who owes it | Deadline | Penalty if missed |
|---|---|---|---|
| Form 5472 + pro forma 1120 | Foreign-owned single-member LLC | April 15 (Oct 15 with 7004); fax/mail only | $25,000 flat per form |
| Form 1120 | C-Corp | April 15 (Oct 15 with 7004) | 5%/mo file + 0.5%/mo pay, each max 25% + interest |
| DE franchise tax + annual report | Delaware C-Corp | March 1 | $200 + 1.5%/mo; loses good standing |
| WY annual report | Wyoming LLC | 1st of anniversary month | Dissolution if 60+ days late |
Do you still file if your company made no money?
Yes — every one of these filings is due annually whether or not the company earned a cent.
This is the single biggest misconception behind the costliest penalties. A foreign-owned LLC with zero revenue still files Form 5472, a C-Corp with no profit still files Form 1120 showing zero, and a dormant entity still owes its state franchise tax and annual report. The IRS and the states tie these obligations to the entity existing, not to it being profitable — so "we didn't operate this year" is not a defense, and a $25,000 Form 5472 penalty has landed on plenty of companies that never opened a bank account.
This article is general information, not legal or tax advice. Penalty figures and deadlines are time-sensitive, so confirm current guidance at irs.gov, your state's site, or with a CPA before you file.
The mistake most guides miss: messy USDC records turn a $0 return into a penalty
For a remote founder, the hard part of these filings is rarely the tax math — it is proving what money moved, especially when revenue and capital arrive as stablecoin across several chains.
Form 5472 specifically asks for reportable transactions between the LLC and its foreign owner: the capital you put in, what you took out, what the company paid on your behalf. A founder invoicing in USD but settling in USDC or USDT on Solana, Ethereum, or Polygon — then off-ramping through a DIY direct-wallet path — ends up with a tangle of on-chain transactions and no clean USD paper trail when that 5472 line asks what happened. That reconstruction-the-night-before-April-15 scramble is exactly how an inactive company misfiles a return and walks into the flat $25,000 penalty.
StableCorp runs the off-ramp on compliant rails with a proper paper trail, so the figures that land on Form 5472, Form 1120, and your state filing are already reconciled — not pieced together from block explorers under deadline. This is the opposite of the regulatory grey area: the grey area is the direct-wallet path, while StableCorp is the compliant solution with a clean record behind every payment.
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. Lower payout cost and audit-ready books on the same return: see pricing for the full schedule.
How do you make sure none of these get missed?
Map every filing to your specific structure on day one, then put each deadline on a calendar — because the right return depends entirely on whether you are an LLC or a C-Corp.
A foreign-owned single-member LLC files Form 5472 with a pro forma 1120 and owes its state annual report; a C-Corp files a full 1120, pays 21%, and owes franchise tax. Pick the wrong mental model and you file the wrong return — or none at all. 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 correct filings are mapped to your structure from the start. Start with pricing to see the all-in cost before your first deadline.
Sources
IRS — About Form 5472 — https://www.irs.gov/forms-pubs/about-form-5472
IRS — Instructions for Form 5472 — https://www.irs.gov/instructions/i5472
IRS — About Form 1120, U.S. Corporation Income Tax Return — https://www.irs.gov/forms-pubs/about-form-1120
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
Delaware Division of Corporations — Annual Report and Tax Instructions — https://corp.delaware.gov/paytaxes/
Wyoming Secretary of State — Business Entities FAQ — https://sos.wyo.gov/faqs.aspx?root=BUS