Can I deduct a 1099 client invoice I never collected?

Yes — under IRC §166, a business can deduct a debt that became totally worthless in the tax year. The debt must have been previously included in gross income (a 1099-MISC, a sale, or a service invoice already reported) and must be supported by documentation of worthlessness — a collection trail, an insolvency filing, or a final demand letter.

What proof do I need for the §166 bad debt deduction?

Documented collection efforts (demand letters, certified-mail notices, phone logs), a counterparty insolvency event (court filing, formal creditor notice, or bankruptcy schedule listing), and bank or accounting records confirming the receivable was reported as income. A year-end write-off memo summarizing all three is the audit-safe package.

Can I deduct a partially worthless business debt?

Yes — under §166(d)(1)(B), a non-bank business can deduct a partially worthless debt, but the election must be made for the taxable year the partial worthlessness occurs. The catch: only specific charge-offs on identified debts qualify. Estimate-based general reserves do not.

What counts as a totally worthless bad debt?

A debt becomes totally worthless when there is no longer any reasonable prospect of collection — bankruptcy of the debtor, expiration of the statute of limitations on the debt, or formal abandonment of the receivable by the creditor. A doubt about collection is not enough; the debt must be provably uncollectible in the deductible year.

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Bad debt deduction (§166)

Bad debt deduction (§166): when 1099 income is uncollectible

Write off a worthless business debt under IRC §166 — insolvency proof, the §166(d)(1) partial-worthless election, amount limitations, and the gross-income inclusion rule.

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Citation backbone

This article rests on the IRC section below — every recommendation Taxerity.AI surfaces cites this same scaffolding.

IRC § 166 IRS Pub. 535

Who can claim this

Who qualifies for the bad debt deduction (§166)

1099-MISC counterparty with documented worthlessness — no collection effort possible after a known insolvency event.

Counterparty insolvency event documented (court filing or formal creditor notice) redacted but timestamp matched to the deductible year.
Collection effort trail (demand letters, complaint of action) on file showing the bad debt became worthless in the deductible year.
Debt ledger ties the amount to a 1099-MISC filing — taxpayer already reported the income, satisfying §166 inclusion in gross income.

How to claim — step-by-step

How to claim the bad debt deduction (§166)on this year's return

Counterparty insolvency event documented (court filing or formal creditor notice) redacted but timestamp matched to the deductible year.
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Collection effort trail (demand letters, complaint of action) on file showing the bad debt became worthless in the deductible year.
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Debt ledger ties the amount to a 1099-MISC filing — taxpayer already reported the income, satisfying §166 inclusion in gross income.
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What catches practitioners off guard

The risk to review

Why AI + human review matters here

§166 only allows a deduction for debts previously included in gross income and only for the amount actually worthless — a debt that became partially worthless needs a year-end §166(d)(1) election, not a full-year write-off.

Taxerity.AI surfaces this and similar items for your firm's reviewer. The AI does the research; you keep the final judgment on whether the workload and evidence pattern warrant the deduction on a specific client's return.

FAQ

Common questions about the bad debt deduction (§166)

Quick answers to the questions solo CPAs and enrolled agents ask us most often about this deduction.

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