Form 5472: The filing your Delaware C-Corp may owe the IRS

What it covers, who has to file, and why a $25,000 penalty has no cap

For Founders

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The IRS doesn't send a reminder. There's no grace period. The first time most foreign founders hear about Form 5472 is after they've already missed it, and by then the $25,000 automatic penalty has already attached.

The form is an information return, not a tax calculation. Its job is to tell the IRS what moved between your US company and its related foreign parties during the year: money, services, IP, property. The IRS uses that picture to check whether your intercompany pricing reflects real market rates, or whether profits are quietly moving to a lower-tax jurisdiction.

Who has to file?

Any US corporation where a foreign person owns 25% or more of the stock at any point during the tax year. And any foreign-owned single-member LLC, which still has to file a pro forma Form 1120 with Form 5472 attached, even if it has no US income.

Revenue doesn't come into it. A company that incorporated in January with no customers still has to file if it had any reportable transaction with a related foreign party. Receiving a capital contribution from your foreign parent counts. A founder loan counts. Signing an intercompany services agreement counts, even if nothing was invoiced yet.

What counts as a reportable transaction?

The obvious ones: sales of goods or services between your US entity and a related foreign party, royalties, management fees, rent, interest on intercompany loans.

Capital contributions are the one that trips people up. When a foreign founder or parent wires money into the US entity at formation, that transfer is reportable. So is converting a loan to equity. The form covers these even though nothing commercial changed hands.

Non-monetary arrangements also go on the form. If your Indian parent provides engineering support to your US entity for free, or at below-market rates, that has to be disclosed and described.

If you have three related parties, you file three forms, all due the same date.

What the IRS is actually looking for

The IRS requires that prices between related parties reflect what unrelated parties would agree to. If your US entity pays your Indian parent $500,000 a year in management fees for work an independent contractor would charge $150,000 for, that gap shifts taxable profit out of the US. That is precisely what Form 5472 is designed to surface.

You don't need a formal transfer pricing study at the early stage. But you do need a written intercompany agreement: what's being provided, at what price, and why that price holds up. An informal understanding between a founder and their own company is not documentation. Putting those agreements in place, and keeping the pricing behind them defensible, is what Caribou does.

When is it due?

April 15 for calendar-year C corporations, alongside Form 1120. Filing Form 7004 by April 15 pushes both to October 15.

If you're in extension territory right now, October 15 is the deadline for the return and any attached Form 5472.

What happens if you miss it

The penalty is $25,000 per form, and it applies whether you filed nothing, filed late, or filed something the IRS considers incomplete.

If the failure continues more than 90 days after the IRS mails notice, the continuation clock starts: another $25,000 per related party for each subsequent 30-day period, with no cap. A filing that stays unfiled long enough can produce a penalty that dwarfs whatever tax the company owed.

There's also a statute-of-limitations consequence. When Form 5472 information is missing, the IRS's window to assess tax on related items stays open until three years after the information is finally furnished. Not three years from the original due date. Three years from when you eventually fix it.

Reasonable cause relief exists. For companies with gross receipts under $20 million, the bar is lower if you had no prior knowledge of the requirement and cooperate quickly. It still requires a sworn written statement and isn't automatic.

How Inkle handles this

Most foreign-founded US companies piece together their compliance from several places: bookkeeping in one tool, a CPA in another, deadlines tracked somewhere no one opens until April. Reconstructing a year's worth of intercompany transactions at filing time is exactly how incomplete returns happen.

Inkle keeps bookkeeping, tax filing, and compliance on one platform built for this structure. Transaction data is logged throughout the year, so when Form 5472 is due, there's nothing to reconstruct. The accountants handle related-party classifications and the filing itself.

Over 2000 US companies use Inkle, including more than 5% of YC companies. If you're not sure whether Form 5472 applies, talk to the team.

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