Doubt as to Liability
The offer in compromise route for disputing that you owe the tax at all. It uses a different form from every other basis — Form 656-L, not Form 656.
Full Definition
Doubt as to Liability is the offer in compromise ground for a taxpayer who disputes the debt itself rather than the ability to pay it. Form 656-B states that if you have a legitimate doubt that you owe part or all of the tax debt, you complete and submit Form 656-L, Offer in Compromise (Doubt as to Liability).
That different form is the practical point. The bases on Form 656 — Doubt as to Collectibility and the two Effective Tax Administration grounds — all begin from the position that the tax is correctly owed and argue about collection. Doubt as to Liability begins somewhere else: it argues the assessment is wrong. Filing it on the wrong form is a real risk, because the two routes are assessed by different parts of the IRS.
What to do next
Request Form 656-L rather than Form 656 — the IRS says it is available on irs.gov, at a local IRS office, or by calling 800-TAX-FORM. If your dispute is about ability to pay rather than whether the tax is right, read Doubt as to Collectibility instead.
What this page does not say
- Form 656-L itself has not been retrieved. What the form requires, how it is evaluated and where it is sent are not described here.
Sources
- Form 656-B, Offer in Compromise Booklet (Rev. 4-2026) — Internal Revenue Service, retrieved 2026-08-20
Last reviewed 2026-08-20 by Tax Resolution Clarity editorial.
Sourced to primary IRS materials and editorially reviewed. Not reviewed by a tax professional. Not tax advice.
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Where to go next
The IRS publishes the rules this page describes. Your own notice governs your dates.