IRC Section 166: Requirements, Reporting, and Recoveries for Bad Debts

A bad debt deduction lets you write off money someone owes you but will not repay, reducing your taxable income under Internal Revenue Code Section 166. Three things have to line up: a real debtor-creditor relationship, your own money (or previously reported income) tied up in the debt, and evidence the debt is worthless. How much you can deduct, and how the loss behaves on your return, depends on whether the debt came out of your business or out of your personal life.

The Three Requirements

First, the debt has to be genuine. That means an enforceable obligation to repay a fixed amount, with both sides intending a loan rather than a gift. A signed promissory note, a stated interest rate, and a repayment schedule are the kind of evidence the IRS looks for. Lend money to a friend or relative on the understanding that repayment is optional, and the tax code treats it as a gift.¹ Gifts are not deductible.

Second, you need basis in the debt. Either you loaned out your own cash, or you already reported the amount as income. This is where cash-basis taxpayers, which includes most individuals, run into trouble. Unpaid wages, fees, rent, interest, or dividends can’t be deducted as bad debts because that money was never on a return to begin with.² The statute limits the deduction to your adjusted basis in the debt under Section 1011, so you can only deduct what you actually had at risk.³

Accrual-basis businesses are in a different position. They record income when it’s earned, so a credit sale that never gets paid was already included in gross income and can be written off when it goes bad.²

Third, the debt must be worthless. More on what that takes below.

Business Debt or Personal Debt Changes Everything

The classification of the debt matters more than almost anything else in this process. It controls how much you can deduct in the current year, whether partial deductions are allowed, and what the loss offsets.

Business Bad Debts

A business bad debt is one created or acquired in your trade or business, or one whose worthlessness is incurred in your business.³ Unpaid customer invoices, loans to employees, and credit extended to suppliers are the usual examples.

Two features make business bad debts much more valuable than personal ones. They are treated as ordinary losses, offsetting regular business income dollar for dollar with no annual cap. And they can be deducted in part: if a specific portion of a debt is clearly uncollectible while the rest might still come in, you can deduct the worthless portion now.³

Nonbusiness Bad Debts

Everything that isn’t a business debt is a nonbusiness debt. Personal loans to friends and family sit here, and the tax treatment is considerably tighter.

A nonbusiness bad debt can only be deducted when it is totally worthless. No partial write-offs. If someone owes you $10,000 and pays back $2,000, you can’t touch the remaining $8,000 as a deduction until any realistic chance of further repayment is gone.¹

The loss is also classified as a short-term capital loss, no matter how long the debt existed.³ That has real consequences. The loss first offsets any capital gains you have for the year. If losses exceed gains, only $3,000 of the remainder can be applied against ordinary income in that year. Anything past that carries forward. A sizable personal loan gone bad can take years of returns to fully deduct.

Proving the Debt Is Worthless

You don’t need a court judgment. The regulation is clear that if surrounding circumstances show the debt is uncollectible and a lawsuit would almost certainly produce nothing, that is enough.⁴ The IRS weighs all available evidence, including collateral and the debtor’s overall financial condition.

Bankruptcy is generally treated as evidence that at least part of an unsecured debt is worthless. In some cases the debt becomes worthless before proceedings end; in others, only when a final distribution is made. If a later event only confirms what was already obvious, the deduction stays in the earlier year.⁴

Other strong indicators: the debtor’s insolvency, the debtor’s disappearance, repeated failed collection attempts, and expiration of the statute of limitations on collecting the debt. Keep records. Demand letters, notes on phone calls, evidence of the debtor’s financial decline, and bankruptcy court correspondence all build the file the IRS will want to see.

The deduction must be claimed in the year the debt actually becomes worthless, not a later year that’s more convenient. If timing is genuinely unclear, claim it earlier rather than later and rely on the extended refund window discussed below.

How to Report It on Your Return

Nonbusiness Bad Debts

Report a totally worthless nonbusiness bad debt as a short-term capital loss on Form 8949, Part I, line 1. In column (a), put the debtor’s name and the phrase “bad debt statement attached.” Enter zero in column (d) and your basis in column (e). Use a separate line for each bad debt. Totals flow to Schedule D of your Form 1040.¹

Attach a separate statement to the return covering:

The amount owed and the date it became due.
The debtor’s name and any business or family relationship you have with the debtor.
The steps you took to collect.
Why you concluded the debt was uncollectible.

This statement is where the IRS looks first. Specific facts about the debtor’s bankruptcy, insolvency, or disappearance carry far more weight than vague assertions.²

Business Bad Debts

Report a business bad debt on the return that matches your entity. Sole proprietors use Schedule C (Form 1040). Corporations use Form 1120. Partnerships and S corporations report on their entity returns, with the loss passing through to partners or shareholders.² Accrual-basis businesses need to confirm the amount was previously included in gross income before claiming the deduction.

What Doesn’t Qualify

Several situations look like bad debts but don’t work under Section 166:

Debts evidenced by a corporate bond, debenture, or other security fall under Section 165(g), not Section 166.³
Unpaid amounts a cash-basis taxpayer never reported as income. That includes unpaid wages, fees, rent, interest, and dividends.²
Money given with no real expectation of repayment. No signed agreement, no interest, no schedule — the IRS treats it as a gift and won’t let you recharacterize the loss later.¹
Shareholder advances that are really capital contributions rather than loans.⁵

If You Later Collect Some of the Money

Sometimes a debt you already wrote off gets paid, in whole or in part. Under the tax benefit rule in IRC Section 111, you generally have to include the recovered amount in gross income for the year you receive it.⁶

One important exception. If the original deduction produced no actual tax benefit, because other losses that year already wiped out your tax, the recovery is excluded from income to that extent.⁶ The rule doesn’t tax you on a reversal of a benefit you never got.

For a business bad debt where you took only a partial deduction, only money attributable to the deducted portion counts as a recovery. Collections on the portion you never wrote off aren’t a recovery and don’t get reported as income.

The Seven-Year Window to Amend

The normal window to amend a return and claim a refund is three years from filing. For bad debts, Congress extended that to seven years.⁷ The seven years run from the original due date of the return for the year the debt became worthless. You file Form 1040-X to claim the refund.¹

The extra time exists because pinpointing the exact year a debt goes bad is often difficult. Financial decline can be gradual, and it may take years before you’re confident the money is gone. If you missed the deduction or picked the wrong year, the seven-year window is the mechanism for fixing it.

1
Internal Revenue Service. Publication 550 – Investment Income and Expenses
2
Internal Revenue Service. Topic No. 453, Bad Debt Deduction
3
Office of the Law Revision Counsel. 26 USC 166 – Bad Debts
4
eCFR. 26 CFR 1.166-2 – Evidence of Worthlessness
5
eCFR. 26 CFR 1.166-9 – Losses of Guarantors, Endorsers, and Indemnitors
6
Office of the Law Revision Counsel. 26 USC 111 – Recovery of Tax Benefit Items
7
Office of the Law Revision Counsel. 26 USC 6511 – Limitations on Credit or Refund