Non-Arm’s Length Transaction: Losses, Imputed Interest, Penalties

Non-arm’s length transaction tax consequences include permanently disallowed losses, capital gains converted to ordinary income, imputed interest on cheap loans, taxable gifts you never meant to make, IRS reallocation of income between your businesses, estate tax surprises, and accuracy-related penalties that run 20 to 40 percent of the underpayment. The federal tax code assumes that people who are related to each other, or businesses under common control, do not bargain the way strangers do, so it treats their deals with skepticism and rewrites the tax results whenever the price strays from fair market value.

The lifetime gift and estate tax exemption is $15,000,000 per person for 2026, which sounds generous until you see how quickly a poorly priced sale to a child or a controlled entity can eat into it.¹ The sections below walk through each consequence, who it applies to, and what documentation actually holds up.

Who the IRS Treats as a Related Party

The definition reaches further than most people expect. For individuals, related parties include your spouse, parents, grandparents, children, grandchildren, and siblings (including half-siblings). For entities, the general threshold is more-than-50-percent common ownership: if one person directly or indirectly controls more than half the stock in a corporation or more than half the capital or profits interest in a partnership, those entities are related to that person and to each other.²

The list also covers trust-related pairings: a grantor and a trustee, a trustee and a beneficiary, two trusts sharing a grantor, and an executor and an estate beneficiary. Tax-exempt organizations you or your family control are in the net as well.²

Ownership is not measured only by what you hold directly. Constructive ownership rules attribute stock held by your family members and by entities you have an interest in back to you. If your spouse owns 40 percent of a corporation and you own 15 percent, the IRS treats you as owning 55 percent when it decides whether you and the corporation are related. A sale that felt arm’s-length can be a related-party transaction without either side realizing it.

Losses on Sales to Related Parties Are Disallowed

Sell property at a loss to a related party and you cannot deduct that loss. The sale price can reflect genuine fair market value, the business reason can be legitimate, and it still does not matter. The loss is permanently disallowed to the seller.²

The buyer gets a partial offset. When the buyer later sells the property to an unrelated third party, gain on that later sale is recognized only to the extent it exceeds the loss that was disallowed to the original seller. The offset is limited to that specific property. If the buyer also sells at a loss, the original seller’s disallowed loss simply disappears with no tax benefit to anyone.

If you are holding an asset with a built-in loss and thinking of selling it to a family member or a controlled entity, the tax cost of the disallowed deduction often outweighs whatever the deal accomplishes. Note also that arranging a sale to an unrelated buyer followed by a prearranged repurchase by a family member can be collapsed under the step-transaction doctrine and treated as a direct related-party sale.

Gains on Depreciable Property Become Ordinary Income

Selling depreciable property to a related party turns what you expected to be capital gain into ordinary income. Any gain the seller recognizes is treated as ordinary income if the buyer can depreciate the property after purchase. Holding period does not save you.³

The rate difference is real money. Long-term capital gains top out at 20 percent for most taxpayers; ordinary income rates reach 37 percent. A business owner selling equipment, a building, or a patent to a controlled entity, expecting capital-gain treatment, will owe ordinary income tax on the entire gain instead.³

For this rule, related persons include a person and any entity they control (more than 50 percent ownership), a taxpayer and a trust where the taxpayer or spouse is a beneficiary, and an executor and estate beneficiary. Constructive ownership counts, so indirect ownership through family or entities can push you over the 50 percent line.

Below-Market Loans Trigger Imputed Interest

Interest-free or below-market loans between family members, employer and employee, or corporation and shareholder are not tax-free arrangements. The IRS treats the loan as if the lender gifted the unpaid interest to the borrower, and the borrower then handed that interest back to the lender. The lender owes income tax on interest never actually received, and the borrower has received either a taxable gift or compensation depending on the relationship.⁴

The benchmark is the Applicable Federal Rate, which the IRS publishes monthly in short-term, mid-term, and long-term versions matched to loan duration. Any loan below the applicable AFR is a below-market loan.⁵

Two exceptions matter for smaller family loans:

Gift loans between individuals are exempt from imputed interest on any day the total outstanding balance between the two people stays at or below $10,000. This exception disappears if the borrower uses any proceeds to buy income-producing assets like stocks or rental property.⁴
For gift loans between individuals where the total outstanding balance does not exceed $100,000, imputed interest income is capped at the borrower’s net investment income for the year. If that net investment income is $1,000 or less, it is treated as zero, so no interest is imputed at all. The cap does not apply if tax avoidance was a principal purpose of the loan.⁴

Below-Market Personal Transfers Are Taxable Gifts

When you transfer property to another person for less than fair market value, the difference is a taxable gift. Intent does not matter. Believing the price was fair does not matter.⁶ A parent who sells a $500,000 house to a child for $200,000 has made a $300,000 gift, regardless of what either party thought.

The first buffer is the annual gift tax exclusion, which allows up to $19,000 per recipient in 2026 with no return required and no lifetime exemption used.¹ Anything above the annual exclusion counts against the $15,000,000 lifetime exemption. Actual gift tax kicks in only after cumulative lifetime gifts exceed that exemption, but Form 709 is required for any year in which a gift to a single recipient exceeds the annual exclusion.⁷

In the house example, the $300,000 deemed gift far exceeds $19,000. The parent files Form 709 and applies $281,000 of lifetime exemption. No tax is due, but the parent’s remaining shelter shrinks by that amount. Because fair market value controls, a qualified independent appraisal of non-cash property transferred between family members is not really optional.

IRS Reallocation of Income Between Commonly Owned Businesses

When two or more businesses share common ownership, the IRS has broad authority to reallocate income, deductions, and credits among them to reflect what each would have earned at arm’s length. The power applies whether the businesses are incorporated or not, domestic or foreign, affiliated or operating independently.⁸

The correct price is whatever unrelated parties would have charged in a comparable situation. Taxpayers are expected to use the pricing method that produces the most reliable answer given the facts, whether that is a comparable uncontrolled price, a comparable profits analysis, or a profit split based on each entity’s economic contribution.

Constructive Dividends

If a corporation sells property to a shareholder below fair market value, the discount can be recharacterized as a constructive dividend. The shareholder picks up taxable income equal to the difference between fair market value and the price paid, and the corporation gets no deduction for the deemed distribution. The same treatment applies when a shareholder uses corporate property without paying full value or receives services at below-market rates.

Rent Between Related Parties

Leasing between related parties is common when a business owner holds real estate in one entity and operates through another. The rent must reflect what an unrelated tenant would pay for comparable space. Rent that is too low lets the IRS impute additional rental income to the landlord. Rent that is too high limits the tenant’s deduction. Square footage, location, building condition, lease term, and local vacancy rates all factor in. A professional appraisal or independent market study dated to the lease signing is the strongest support.

Estate Tax and Family Buy-Sell Agreements

Closely held businesses often set the price for a deceased owner’s interest through a buy-sell agreement. When the owners are family members, the IRS suspects the price is suppressed to shift wealth without full estate tax. The agreement’s price is disregarded unless it meets all three of the following:

It is a bona fide business arrangement.
It is not a device to transfer the business interest to family members for less than adequate consideration.
Its terms are comparable to what unrelated persons would agree to at arm’s length.⁹

Fail any of the three, and the IRS values the business interest at fair market value on the date of death. The estate then owes tax on the higher amount even when it remains contractually bound to sell at the lower price, creating a cash-flow gap that can be severe.

A separate rule pulls certain transfers back into the estate if made within three years of death. If the decedent transferred an interest in property (subject to a retained life estate, held in a revocable trust, or a life insurance policy, for example) that would have been included in the gross estate had the decedent kept it, the full value snaps back. Bona fide sales for adequate and full consideration are outside this rule.¹⁰

Foreign-Owned Entities Have Their Own Reporting Trap

If a U.S. corporation is 25 percent foreign-owned, it must file Form 5472 to report related-party transactions. A single-member LLC that is 100 percent foreign-owned must also file, even with no U.S. income. The penalty for each failure to file a complete and correct Form 5472 by the deadline is $25,000. If the IRS sends a notice and the form is still not filed within 90 days, another $25,000 accrues for each 30-day period the failure continues. There is no cap.¹¹ Missed for several years, the accumulated penalties can dwarf any underlying tax.

Accuracy-Related Penalties for Valuation Misstatements

Getting the valuation wrong on a related-party transaction opens two tiers of accuracy-related penalties.

For property valuations on income tax returns, a substantial valuation misstatement exists when the claimed value is 150 percent or more of the correct value, and the penalty is 20 percent of the tax underpayment. When the claimed value hits 200 percent or more of the correct value, it becomes a gross valuation misstatement and the penalty doubles to 40 percent.¹²

Transfer pricing adjustments between related businesses have their own triggers. A 20 percent penalty applies when the net transfer pricing adjustment exceeds the lesser of $5 million or 10 percent of the taxpayer’s gross receipts for the year. That penalty rises to 40 percent when the net adjustment exceeds $20 million or 20 percent of gross receipts.¹²

Documentation That Actually Holds Up

Contemporaneous documentation is the strongest defense against every consequence above. For transfer pricing between related businesses, that means a formal study prepared before the return is filed, analyzing each entity’s functions, risks, and assets and explaining why the chosen pricing method produces an arm’s-length result. The study does not have to prove the price was perfect; it has to show a reasonable effort was made.

For personal transfers of non-cash property between family members, a qualified independent appraisal is essential. The appraiser should hold a recognized professional designation and have demonstrated competence with the type of property involved. The appraisal should be completed close to the transfer date and attached to the relevant tax return.

Loans between related parties need written agreements specifying the amount, interest rate, repayment schedule, and maturity date. If the rate meets or beats the AFR, the written agreement does most of the work. If the rate is below the AFR, both parties need to understand the imputed interest consequences and report them consistently.

For family buy-sell agreements, back the price with a current business valuation from an independent firm and update it periodically, especially after significant changes in the business. A five-year-old valuation will not convince the IRS that today’s contract price is what unrelated owners would negotiate.

All of this documentation supports a reasonable cause and good faith defense. Even where the IRS adjusts a valuation, a well-prepared study or appraisal already in the file when the return was filed can eliminate the accuracy-related penalties entirely. The penalties target carelessness and gamesmanship, not honest disagreements about value backed by credible analysis.

1
Internal Revenue Service. What’s New – Estate and Gift Tax
2
Office of the Law Revision Counsel. 26 USC 267 – Losses, Expenses, and Interest With Respect to Transactions Between Related Taxpayers
3
Office of the Law Revision Counsel. 26 USC 1239 – Gain From Sale of Depreciable Property Between Certain Related Taxpayers
4
Office of the Law Revision Counsel. 26 USC 7872 – Treatment of Loans With Below-Market Interest Rates
5
Internal Revenue Service. Applicable Federal Rates Rulings
6
Office of the Law Revision Counsel. 26 USC 2512 – Valuation of Gifts
7
Internal Revenue Service. Gifts and Inheritances
8
Office of the Law Revision Counsel. 26 USC 482 – Allocation of Income and Deductions Among Taxpayers
9
Office of the Law Revision Counsel. 26 USC 2703 – Certain Rights and Restrictions Disregarded
10
Office of the Law Revision Counsel. 26 USC 2035 – Adjustments for Certain Gifts Made Within 3 Years of Decedent’s Death
11
Office of the Law Revision Counsel. 26 USC 6038A – Information With Respect to Certain Foreign-Owned Corporations
12
Office of the Law Revision Counsel. 26 USC 6662 – Imposition of Accuracy-Related Penalty on Underpayments