TC 351: Negligence Penalty Abatement

What the code actually does

IRS Document 6209 defines TC 351 plainly: "Negligence Penalty Abatement... Abates a previously posted TC 350 in whole or in part." It is a credit — it reduces the module (the IRS's record for one tax period within the account) balance — and it cannot post without a prior TC 350 already on the account, since there is nothing for it to abate otherwise.

The abatement can be partial. A TC 351 for less than the original TC 350 amount typically means the IRS or Appeals recalculated the portion of the underpayment actually attributable to negligence, rather than agreeing that no negligence occurred at all — the practical distinction that determines whether the case is fully resolved or only partly so.

Why a penalty gets abated

IRM 20.1.5, Return Related Penalties, governs negligence under the same section (20.1.5.8/20.1.5.8.1) that establishes when the penalty applies in the first place — abatement follows the same legal framework in reverse. The most common basis is a reasonable-cause showing under IRC §6664(c) — a separate statute from the one that creates the penalty — which the taxpayer uses to demonstrate the underpayment was not, in fact, the product of unreasonable conduct as IRC §6662(b)(1) and (c) define it, defeating the negligence theory even after an initial assessment. The same IRM chapter's reasonable-cause section frames that showing around the taxpayer's own effort to report the correct liability, plus factors like experience, knowledge, and education — evidence a taxpayer typically has to assemble and present after the TC 350 has already posted, which is why a successful reasonable-cause claim can take time to work through even when it ultimately succeeds in full — the abatement rarely posts the same day the argument is made.

A TC 351 can also follow a straightforward computational correction — for example, if the original TC 350 amount was calculated against a larger underpayment figure than ultimately survived examination or Appeals review, the penalty base shrinks and the abatement follows the tax adjustment rather than reflecting any change in the negligence determination itself.

What this means for the account

A TC 351 means money is coming off the module, but the size of the abatement relative to the original TC 350 tells the real story: a full abatement usually means the negligence determination itself did not survive review (a successful reasonable-cause claim, an Appeals concession, or a Tax Court resolution), while a partial abatement more often tracks a reduced tax underpayment or a scaled-back penalty computation.

Confirm what actually drove the abatement before advising a client on the state of the case — a partial TC 351 following a reasonable-cause argument that only partly succeeded is a different situation from a partial TC 351 that simply followed a separate reduction in the underlying tax.

What TC 351 gets confused with

TC 351 is specific to the negligence penalty and should not be read as a general abatement code. TC 321, the civil fraud penalty abatement, reverses a fraud assessment under an entirely different legal standard and burden of proof — confusing the two risks describing the wrong theory as having been defeated.

It is also not a statement that the return itself was correct. TC 351 only removes the negligence penalty; if the underlying tax adjustment from the same examination remains on the account, the taxpayer may still owe the additional tax and any applicable interest even after the negligence penalty is fully abated.

The practitioner's actual next step

Compare the TC 351 amount to the original TC 350 assessment to determine whether the abatement is full or partial, and request the case history to learn why.

If the abatement is partial, verify whether it tracks a reduced tax underpayment or a scaled-back penalty computation before concluding the negligence issue itself is only partly resolved.

Confirm whether the underlying tax adjustment from the same examination is still on the account — a negligence penalty abatement does not by itself resolve the tax or interest.

Pull the complete account history with the IRS Transcript Decoder to see the full sequence of the original TC 350 assessment and this TC 351 abatement together.