The interest rate on a loan between related companies has to look like something an unrelated lender would have charged. The cleanest way to get there is the IRS safe harbor under Treasury Regulation ยง 1.482-2: any rate between 100% and 130% of the Applicable Federal Rate for the loan’s term is accepted as arm’s length without further analysis.1eCFR. 26 CFR 1.482-2 – Determination of Taxable Income in Specific Situations Charge less than the floor, or nothing at all, and the IRS can impute interest income to the lender, adjust the borrower’s deduction, and add accuracy-related penalties of 20% or 40% on the resulting underpayment.
How the AFR Safe Harbor Works
The AFR you use depends on how long the loan runs:
- Short-term, 3 years or less: the Federal short-term rate
- Mid-term, more than 3 but not more than 9 years: the Federal mid-term rate
- Long-term, more than 9 years: the Federal long-term rate
The IRS publishes updated AFRs each month by revenue ruling. For January 2026, the annual-compounding rates are 3.63% short-term, 3.81% mid-term, and 4.63% long-term.2Internal Revenue Service. Revenue Ruling 2026-2 Each rate reflects the average market yield on outstanding U.S. government obligations of matching maturity.3Office of the Law Revision Counsel. 26 USC 1274(d) – Determination of Applicable Federal Rate
You lock in the rate when the loan is made. The regulations let you pick the AFR in effect for the month of the loan or for either of the two preceding months, so you can choose the most favorable of three consecutive months’ rates.1eCFR. 26 CFR 1.482-2 – Determination of Taxable Income in Specific Situations Demand loans are different: the applicable rate is the Federal short-term rate, redetermined each day the loan stays outstanding.
The corridor works in both directions. If the stated rate is below 100% of the AFR, the IRS treats the arm’s length rate as the AFR floor, compounded semiannually. If it exceeds 130%, the arm’s length rate is capped at 130% compounded semiannually, unless a full comparability study supports going higher.
When You Can’t Use the Safe Harbor
Two hard exclusions take the safe harbor off the table. It doesn’t apply to any loan denominated in a foreign currency, and it doesn’t apply if the lender regularly makes loans to unrelated parties as part of its trade or business. In that second case, the arm’s length rate is whatever the lender actually charges independent borrowers on similar loans.
The safe harbor also assumes the transaction is bona fide debt. If the IRS concludes the “loan” is really equity, the rate question never gets reached. More on that below.
Intercompany Trade Receivables
Ordinary intercompany invoices get a grace period before interest has to accrue. For domestic transactions, no interest is required until the first day of the third calendar month after the receivable arises. If the debtor’s trade or business is outside the United States, the grace period runs to the first day of the fourth calendar month.4eCFR. 26 CFR 1.482-2 – Determination of Taxable Income in Specific Situations Routine 30- and 60-day invoicing between related companies doesn’t become a transfer pricing problem.
Pricing a Loan Outside the Safe Harbor
When you’re outside the corridor by choice or by exclusion, the interest rate has to be justified as arm’s length under a full analysis. The starting question is what an independent lender would charge an independent borrower for a comparable loan. The regulation lists the factors that matter: principal amount and duration, whether the loan is secured, the borrower’s credit standing, and prevailing rates for similar loans in the lender’s market. All relevant factors should be considered, and the analysis should reflect conditions at the time the loan was made.
The most defensible approach, when the data exists, is the Comparable Uncontrolled Transaction method: find similar loans between unrelated parties and price to them. When comparables are thin, other transfer pricing methods may apply, but under the best method rule the taxpayer has to use whichever method produces the most reliable measure of an arm’s length result, regardless of preference.5Internal Revenue Service. 26 CFR 1.482-1(c) – Best Method Rule
Implicit Support
Assessing a subsidiary’s credit standing is the hardest piece. A subsidiary standing alone might be a mediocre credit, but the market prices in the likelihood that a parent would support it before letting it default. In AM 2023-008, the IRS took the position that this implicit support should be reflected in the intercompany rate: if expected parental backing strengthens the borrower’s real-world credit profile, using the standalone rating overstates the arm’s length rate. The likelihood of support has to be established with objective evidence, including the group’s history and the subsidiary’s strategic role. Passive benefits of group membership don’t require compensation, but realistic support does.
Section 7872: A Second Layer for Corporation-Shareholder Loans
Section 482 isn’t the only rule policing intercompany interest. Section 7872 applies separately to below-market loans in several categories, including any loan between a corporation and a shareholder.6Office of the Law Revision Counsel. 26 USC 7872 – Treatment of Loans With Below-Market Interest Rates If a demand loan carries a rate below the AFR, or a term loan is made for more than the present value of all payments due under it, Section 7872 treats the shortfall as a deemed transfer from the lender to the borrower and a deemed interest payment back. Between a corporation and a shareholder, the deemed transfer runs as a distribution one way and a capital contribution the other.
Section 7872 has a $10,000 de minimis exception for compensation-related and corporation-shareholder loans, available on any day the aggregate outstanding balance stays at or below that threshold. The exception disappears entirely if tax avoidance is one of the principal purposes of the interest arrangement.
Both provisions can bite the same loan. A parent-subsidiary advance that clears Section 482 may still trigger Section 7872 if it dips below the AFR floor, so both need to be checked when the rate is set.
Before Anything Else: Is It Actually a Loan?
None of the rate analysis matters if the IRS recharacterizes the transaction as equity. Genuine debt has a fixed maturity, an unconditional repayment obligation, actual payment history, a defensible debt-to-equity ratio, and terms an outside lender might have accepted. Advances that are open-ended, contingent on profitability, routinely deferred, or made in proportion to ownership look like capital contributions. If the IRS recharacterizes, the borrower’s “interest” deduction disappears entirely, and cross-border transactions can pull the lender into a cascade of international reporting obligations. The rate on the paper matters only after the paper survives.
What Happens If the Rate Is Wrong
When the IRS finds the rate off, it makes a primary adjustment: imputed interest income to the lender if the rate was too low, disallowed interest deduction to the borrower if the rate was too high. That adjustment then triggers secondary adjustments to account for where the cash actually went, which may be treated as a constructive dividend, a capital contribution, or another deemed transfer depending on the relationship. Constructive dividends to foreign shareholders can pull in withholding tax obligations of their own.7Internal Revenue Service. Transfer Pricing
On top of the tax, Section 6662(e) adds accuracy-related penalties in two tiers:
- 20% substantial valuation misstatement penalty when the claimed price is 200% or more, or 50% or less, of the correct arm’s length price, or when the net Section 482 adjustment for the year exceeds the lesser of $5 million or 10% of gross receipts.8Office of the Law Revision Counsel. 26 U.S. Code 6662 – Imposition of Accuracy-Related Penalty on Underpayments
- 40% gross valuation misstatement penalty when the price is 400% or more, or 25% or less, of the correct amount, or when the net adjustment exceeds the lesser of $20 million or 20% of gross receipts.
Contemporaneous documentation that meets the regulatory standards is the primary defense against both penalty tiers. Without it, the accuracy-related penalty is much harder to fight off.
Form 5472 for Foreign-Owned Entities
If the borrower or lender is a U.S. corporation that is 25% or more foreign-owned by vote or value, or a foreign-owned single-member LLC treated as a disregarded entity, transactions with foreign related parties get reported on Form 5472. That includes loan originations, interest payments, and principal repayments. The penalty for failing to file, or filing a substantially incomplete return, is $25,000 per related party per taxable year, with an additional $25,000 for each 30-day period the failure continues after the IRS mails a notice past the 90-day mark.9eCFR. 26 CFR 1.6038A-4 – Monetary Penalty Pricing the loan inside the AFR safe harbor doesn’t excuse the reporting.
Documentation That Holds Up
The starting piece is a written loan agreement, signed by both parties at or before the funds move, that spells out principal, interest calculation, repayment schedule, maturity, collateral, and default terms. These terms serve double duty: they support the interest rate position and they help establish that the transaction is bona fide debt.
You also need to document how the rate was set. For safe harbor loans, that means recording which month’s AFR was used, the term bracket it came from, and confirmation that the rate lands between 100% and 130% of that AFR. For loans priced outside the safe harbor, a transfer pricing study should lay out the methodology, the comparables or data relied on, and why the chosen method produces the most reliable arm’s length result under the best method rule.
Corporate authorizations should be contemporaneous. Board resolutions or minutes approving the loan, executed at the time rather than reconstructed later, are among the first things the IRS looks for when testing whether a transaction is real.
Transfer pricing documentation must generally exist by the time the return is filed for the year in question, and it must be produced within 30 days of an IRS request during examination.10Internal Revenue Service. Transfer Pricing Documentation Best Practices Frequently Asked Questions (FAQs) Documentation assembled during an audit doesn’t meet the contemporaneous standard, and its absence is what turns a rate dispute into a penalty case.