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972CG reasonable cause, explained

Reasonable cause is the relief valve in every Notice 972CG response — but it is a defined legal test, not a plea for sympathy. Reg. §301.6724-1 sets out exactly what the IRS must see. Here's the test, the evidence it demands, and what happens after you submit it.

The two-prong test

Reg. §301.6724-1 grants relief from §6721 penalties only when the filer establishes reasonable cause — and the regulation defines it as two prongs, both required:

• (A) There were significant mitigating factors with respect to the failure, or the failure arose from an impediment beyond the filer's control; and
• (B) the filer acted in a responsible manner both before and after the failure occurred.

A strong excuse with sloppy follow-through fails prong (B). Diligent correction of a failure with no real cause fails prong (A). The statement has to carry both.

Source: Reg. §301.6724-1 (eCFR).

Prong one: mitigating factors or impediment

The regulation lists specific categories of impediments beyond the filer's control — events the filer could not reasonably have prevented. The list is not open-ended; the facts have to fit a recognized category:

• Business records unavailable because of a supervening event — fire or other casualty, a last-minute change in the law or regulations, or the unavoidable absence (death or serious illness) of the person with sole responsibility for filing.
• Undue economic hardship tied to magnetic-media filing requirements (a narrow, hardware-cost test).
• Reasonable reliance on erroneous written IRS information — you must be able to produce the IRS writing.
• Actions of the filer's agent — reasonable cause is imputed if you exercised reasonable business judgment in hiring and supplying the agent, and the agent itself meets one of the recognized grounds.
• Actions of the payee or another person — the payee failed to provide information, or provided incorrect information you relied on in good faith (documentary evidence required if the IRS asks).

Source: Reg. §301.6724-1(c).

Practically, this means the statement must identify what happened in concrete terms — not "we had issues," but the specific event, when it occurred, and why it prevented timely correct filing. Vague assertions don't satisfy the prong.

Source: Reg. §301.6724-1.

Prong two: responsible manner

"Responsible manner" is judged on conduct before and after the failure:

• Before: did the filer take reasonable steps to avoid the failure — e.g., requesting filing extensions where available, maintaining compliance procedures, training the people who handle the returns?
• After: once the failure was discovered, did the filer promptly rectify it? The regulation treats correction ordinarily within 30 days of discovery as the benchmark for promptness.

This is why correction timing matters twice: it sets the penalty tier under §6721 and it feeds prong (B). File corrected returns as soon as possible — see What is Letter 972CG? for how corrections are filed.

Source: Reg. §301.6724-1.

TIN failures and the solicitation regime

Missing or incorrect TINs (PRN 502) get their own detailed regime. The regulation expects the filer to have solicited the TIN:

• An initial solicitation — generally a Form W-9 request when the relationship begins; and
• Annual solicitations thereafter for payees whose TINs remain missing or incorrect.

Relying on electronic-only processes to collect TINs is not sufficient under the regime. The paper trail of requests — dates, methods, responses — is the evidence prong (B) runs on for TIN failures.

Source: Reg. §301.6724-1.

The four written-statement requirements

Reg. §301.6724-1(m) is explicit: a reasonable-cause request must contain all four of the following, or it is procedurally defective:

1. Cite the provision under which relief is sought (reasonable cause under §6724).
2. State all facts that establish reasonable cause — the full factual basis, not a summary.
3. Be signed by the filer (the person required to file the return).
4. Include a declaration that the statement is made under penalties of perjury.

A statement missing any one of these can be rejected on procedural grounds without reaching the merits.

Source: Reg. §301.6724-1(m).

Common documentation

The facts in the statement need support. What "support" means depends on the failure, but the pattern is consistent — contemporaneous records tying each claimed fact to a date:

• Late filing: extension requests, transmission logs, e-file acknowledgments, records of the event that caused the delay.
• TIN failures: W-9 requests with dates, annual solicitation records, responses received.
• E-file failures: evidence of the filer's return count, filing method used, and any vendor or system records.
• Corrections: copies of the corrected returns filed, transmittal records, and proof of furnishing corrected statements to payees — with dates, because timing sets the tier.

Assemble the evidence as an index tied to the months and failures it supports — the same discipline as the 14765 evidence checklist, applied to a different notice.

What the IRS does next

After you submit your response, the IRS replies with one of two letters:

• Letter 1948-C — the IRS needs more information, or is granting your written extension request (up to 90 days from the notice date).
• Letter 854-C — the waiver is disallowed, with appeal rights. A disallowed waiver can be taken to the IRS Office of Appeals.

Sources: IRM 4.19.25; Reg. §301.6724-1.

Common questions

This guide is general information, not legal or tax advice. Statutes and IRS pages change — verify against the sources linked above.