The imputed interest rate is the minimum interest rate the IRS requires on certain loans and deferred-payment property sales, regardless of what the parties actually agreed to charge. That minimum is the Applicable Federal Rate (AFR), which the IRS publishes each month. Charge at least the AFR and the rules leave you alone. Charge less, and the IRS treats the missing interest as though it were paid: the lender owes income tax on interest never actually collected, and in a family loan the shortfall can also count as a taxable gift.
How the Applicable Federal Rate Sets the Floor
The AFR is drawn from average yields on U.S. Treasury securities and published each month in a Revenue Ruling on irs.gov.1Internal Revenue Service. Revenue Ruling 2026-2 It comes in three tiers based on the loan’s term: short-term for loans of three years or less, mid-term for loans over three years and up to nine, and long-term for anything longer. Each tier is published for annual, semiannual, quarterly, and monthly compounding, and the monthly compounding figure is always slightly lower than the annual, so picking monthly compounding gives you the lowest permissible rate.
You lock in the AFR for the month the loan is made. Later movements in the published rate do not change your obligation on that loan. Check the current ruling before finalizing the paperwork and write the chosen rate into the loan document.
Family Loans: Where Imputed Interest Bites Most Often
The most common trigger is a loan between relatives, which the IRS calls a gift loan and governs under Section 7872. A parent lending a child money for a house, siblings splitting a property purchase, grandparents funding a business: all of these fall under the rule if the interest rate charged is below the AFR.2Office of the Law Revision Counsel. 26 USC 7872 – Treatment of Loans With Below-Market Interest Rates Three thresholds decide how hard the rule hits.
Loans of $10,000 or Less
If the total outstanding loans between two people stay at or below $10,000, Section 7872 does not apply. You can lend a family member $10,000 at zero interest and owe nothing extra. The exception disappears if the borrower uses the money to buy income-producing assets like stocks or rental property.
Loans Between $10,001 and $100,000
In this middle tier, the imputed interest rules technically apply, but the amount you owe income tax on is capped at the borrower’s net investment income for the year. Lend your son $80,000 interest-free while he earns only $600 in investment income, and the imputed interest is limited to $600. If the borrower’s net investment income is $1,000 or less, it is treated as zero, so no imputed interest is recognized for income-tax purposes. Most family loans land here, and many produce no income-tax liability. The gift-tax analysis still runs on its own track.
Loans Above $100,000
Once the outstanding balance between the two people crosses $100,000, the net investment income cap disappears. The full AFR applies to the entire balance, and the lender must recognize the full foregone interest as income each year. This is where imputed interest turns into a real recurring tax cost.
Employer and Corporate Loans
Below-market loans outside families get taxed by their character. When an employer lends to an employee at a below-market rate, the foregone interest is treated as extra compensation: taxable wages to the employee, deductible compensation expense to the employer. When a corporation lends to a shareholder, the foregone interest is treated as a dividend: taxable to the shareholder, not deductible by the corporation.
Both categories share the $10,000 de minimis exception, but with a backstop the family rule does not have. If one of the principal purposes of the interest arrangement is federal tax avoidance, the exception is unavailable regardless of loan size.
Installment Sales and Deferred Payments
A separate set of rules covers property sold with payments due more than a year after the sale. If the contract does not state adequate interest at or above the AFR, the IRS recharacterizes part of each payment as interest rather than sale proceeds. Section 483 handles most property sales and does not apply at all when the sale price is $3,000 or less.3Office of the Law Revision Counsel. 26 USC 483 – Interest on Certain Deferred Payments Section 1274 covers larger debt instruments issued for property.4Office of the Law Revision Counsel. 26 USC 1274 – Determination of Issue Price in the Case of Certain Debt Instruments Issued for Property
Family land sales get a break. For sales of land between related parties totaling no more than $500,000 in a calendar year, Section 483 caps the imputed rate at 6% compounded semiannually, even when the AFR is higher.
The recharacterization matters because interest income is usually taxed at higher rates than long-term capital gains. When part of a property payment gets reclassified as unstated interest, the seller’s capital gain shrinks and ordinary interest income grows, raising the total tax bill.
What Phantom Income Actually Costs You
Phantom income describes what happens on the lender’s return: tax on money that never arrived. Lend your brother $200,000 at zero interest when the AFR is 4%, and the IRS treats roughly $8,000 a year as interest you earned. That $8,000 goes on your return as interest income even though your brother has sent you nothing beyond principal repayments.
For gift loans the mechanics run in two steps. The lender is treated as giving the borrower the foregone interest as a gift, and the borrower is treated as paying that same amount back to the lender as interest. The lender ends up with taxable interest income and a possible gift-tax filing. The borrower ends up with a deemed interest payment that is generally not deductible, because the IRS classifies it as personal interest. Only if the loan proceeds went to a deductible use, such as a qualifying home purchase or a business investment, might the borrower claim a deduction. The one-sided outcome is the real sting: tax on paper income, with no offsetting benefit on the other side.
How to Report It
Lenders report imputed interest income on Schedule B, the same place ordinary bank interest goes. If the foregone interest on a gift loan exceeds the annual gift-tax exclusion, the lender also files Form 709.5Internal Revenue Service. Instructions for Form 709
Employer-employee and corporate-shareholder loans follow the character of the deemed transfer. Compensation-related imputed interest shows up on the employee’s W-2. Dividend-related imputed interest goes on a 1099-DIV. Form 1099-INT is required for interest of $10 or more to a recipient in a tax year, and that threshold applies to imputed interest the same way it applies to actual interest.6Internal Revenue Service. Topic No. 403, Interest Received
Before making any loan large enough to fall outside the $10,000 de minimis rule, pull the current AFR, write the rate into a signed note, and set a reminder to report the interest each year it accrues. That short list of steps is what separates a straightforward family loan from an audit-year surprise.