Does my accountant's mistake shield me from the IRS?

    The claim: “If my accountant made the mistake, I'm not responsible to the IRS.”

    False: the tax stays yours; penalty relief depends on facts

    No. The tax you owe is your liability even when a preparer caused the error, and interest generally runs on it. What may be removed is the penalty: IRC §6664(c) bars the §6662 accuracy-related penalty for any portion of an underpayment where you show reasonable cause and good faith, such as reasonable reliance on a competent professional you gave complete and accurate information.

    Reviewed by Ebot Mbi, CPA, EA · Last reviewed · Law and figures current as of September 17, 2026

    Key takeaways

    • You sign your return under penalties of perjury, and the tax on it is your liability.
    • The accuracy-related penalty under IRC §6662 is generally 20% of the underpayment it applies to.
    • IRC §6664(c) can remove that penalty if you show reasonable cause and good faith; Treas. Reg. §1.6664-4 sets the standards for reliance on advice.
    • First-time abatement does not apply to accuracy-related penalties, and interest on the tax is generally not removed because of a preparer's error.
    • A preparer who is at fault may face separate preparer penalties, but that does not reduce your tax.

    Where the claim comes from

    Many taxpayers assume that hiring a professional transfers responsibility for the return. When a notice arrives, the first reaction is often that the preparer made the mistake, so the IRS should look to the preparer.

    There is a real legal rule behind part of that instinct. Reliance on a professional can matter, but only for penalties, and only when the facts support it.

    What the law actually says

    The tax shown on your return, and any additional tax determined later, is your liability. Interest generally accrues on unpaid tax from the original due date until it is paid, and the rules for abating interest are narrow and do not cover preparer errors.

    IRC §6662(a) adds a penalty equal to 20% of the portion of an underpayment attributable to negligence, disregard of rules, a substantial understatement of income tax, and certain other causes. IRC §6664(c)(1) provides that no penalty is imposed under §6662 or §6663 on any portion of an underpayment if you show reasonable cause for that portion and that you acted in good faith.

    Treas. Reg. §1.6664-4(b)(1) makes this a case-by-case determination based on all pertinent facts and circumstances. For reliance on professional advice, §1.6664-4(c)(1) requires, at a minimum, that the advice be based on all pertinent facts and circumstances, and that it not rest on unreasonable factual or legal assumptions. The Tax Court often frames the question as whether the adviser was a competent professional with enough expertise to justify reliance, whether you provided necessary and accurate information, and whether you actually relied on the advice in good faith (Neonatology Associates, P.A. v. Commissioner, 115 T.C. 43 (2000)).

    IRM 20.1.1.3.2 describes reasonable cause as based on all the facts and circumstances, and IRM 20.1.1.3.2.2.5 addresses claims based on erroneous advice or reliance on others. Under IRM 20.1.1, first-time abatement applies to failure-to-file, failure-to-pay, and failure-to-deposit penalties, not to accuracy-related penalties. Reasonable cause cannot excuse the portion of an underpayment tied to a transaction lacking economic substance under IRC §6664(c)(2).

    What is true and what is not

    It is true that a preparer's error can support penalty relief when you gave the preparer complete and accurate records, the error involved a question you could reasonably rely on a professional to answer, and you had no reason to doubt the result. It is also true that a preparer can be subject to separate penalties under IRC §6694.

    It is not true that the IRS will look only to the preparer. The additional tax remains yours, and interest on it generally remains too. Reliance does not help if you withheld information, ignored obvious problems on the return, or did not review what you signed.

    • Additional tax: owed by you.
    • Interest on that tax: generally owed by you.
    • Accuracy-related penalty: may be removed if reasonable cause and good faith are shown.
    • Your recourse against the preparer: a separate matter between you and the preparer.

    What to do instead

    Give your preparer complete records, answer their questions fully, and review the return before you sign it. Ask about any entry you do not understand. Keep copies of what you provided and any written advice you received, since those documents are the evidence for a reasonable cause request.

    If a notice arrives that traces to a preparer error, respond by the deadline, pay or arrange to pay the tax to limit further interest, and request penalty relief with a written explanation and supporting documents. Review your engagement letter to understand what the preparer agreed to do.

    How ebotCPA helps

    We review the notice and the return, identify what went wrong, and prepare a reasonable cause request built on your records and the regulation's standards. We also explain your options for resolving the balance.

    Book a $497 Case Analysis to have Ebot Mbi, CPA, EA review your facts before you act.

    Preparer error that understates tax

    Assumptions: Tax year 2026 return; an error understates tax by $50,000, which is a substantial understatement.; The IRS asserts the 20% accuracy-related penalty under IRC §6662(a).; Scenario B assumes the taxpayer establishes reasonable cause and good faith under IRC §6664(c). Interest is not computed.

    Additional tax owed$50,000
    Accuracy-related penalty (20% × $50,000)$10,000
    Scenario A total, before interest$60,000
    Scenario B penalty after reasonable cause relief$0
    Scenario B total, before interest$50,000

    Under these assumptions, reasonable cause relief removes the $10,000 penalty, but the $50,000 of tax and the interest on it remain owed.

    Illustration only; not a projection of your results.

    Primary sources

    1. 26 U.S.C. §6664(c)(1). Reasonable cause exception for underpayments.
      “No penalty shall be imposed under section 6662 or 6663 with respect to any portion of an underpayment if it is shown that there was a reasonable cause for such portion and that the taxpayer acted in good faith with respect to such portion.”

      Provides penalty relief only; it does not reduce the underlying tax.

    2. 26 U.S.C. §6662(a). Accuracy-related penalty.
      “If this section applies to any portion of an underpayment of tax required to be shown on a return, there shall be added to the tax an amount equal to 20 percent of the portion of the underpayment to which this section applies.”

      Sets the 20% accuracy-related penalty.

    3. Treas. Reg. §1.6664-4(b)(1), (c)(1). Reasonable cause and reliance on advice.
      “The advice must be based upon all pertinent facts and circumstances and the law as it relates to those facts and circumstances.”

      Makes reasonable cause a facts-and-circumstances test and sets minimum requirements for reliance on professional advice.

    4. IRM 20.1.1.3.2 and 20.1.1.3.2.2.5. Reasonable cause; erroneous advice or reliance.
      “Reasonable cause is based on all the facts and circumstances in each situation and allows the IRS to provide relief from a penalty that would otherwise apply.”

      IRS guidance for evaluating reasonable cause, including claims based on reliance on others.

    5. Neonatology Associates, P.A. v. Commissioner, 115 T.C. 43 (2000), aff'd, 299 F.3d 221 (3d Cir. 2002). Three-part reliance test.

      Frames reliance as requiring a competent adviser, full and accurate information from the taxpayer, and actual good-faith reliance.

    Frequently asked questions

    Who pays if my tax preparer makes a mistake?

    You owe the additional tax and generally the interest. Penalties may be removed if you show reasonable cause and good faith. Any claim against the preparer is a separate matter.

    Can the IRS remove interest caused by a preparer error?

    Generally no. Interest abatement is limited and does not cover errors by your own preparer. Interest may be reduced only to the extent the related penalty is removed.

    Does first-time abatement cover accuracy penalties?

    No. Under IRM 20.1.1, first-time abatement applies to failure-to-file, failure-to-pay, and failure-to-deposit penalties, not to the accuracy-related penalty.

    What do I need to show reasonable cause based on a preparer's error?

    Evidence that the preparer was competent, that you gave complete and accurate information, and that you relied on the preparer's work in good faith, such as your records, correspondence, and the engagement letter.

    Have facts like these?

    Book a $497 Case Analysis to have Ebot Mbi, CPA, EA review your facts before you act.

    General information, not tax, legal, or investment advice for your situation. Results depend on your facts; no outcome is guaranteed. Reading this page does not create a client relationship.

    ebotCPA PLLC · Ebot Mbi, CPA (Texas License #127163), Enrolled Agent · 4425 W Airport Fwy, Ste 595, Irving, TX 75062

    Last updated: September 12, 2026