IRS Negligence Penalty: IRC §6662(c)
The IRS imposes a 20% negligence penalty when you fail to make a reasonable attempt to comply with tax laws. Poor recordkeeping, unsubstantiated deductions, and careless disregard of IRS rules can all trigger this penalty — but strong defenses exist, including reliance on a qualified tax professional. Here's what negligence means, what triggers it, and how to fight back.
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What Is the Negligence Penalty?
The negligence penalty is one of the most frequently assessed IRS penalties — and one of the most commonly misunderstood.
The negligence penalty is codified at Internal Revenue Code §6662(c) as one form of the accuracy-related penalty. Under this provision, if any portion of an underpayment of tax is attributable to negligence or disregard of rules and regulations, a penalty equal to 20% of that portion is added to the tax. The penalty applies regardless of whether the error was intentional — the standard is whether the taxpayer failed to make a reasonable attempt to comply with the provisions of the Internal Revenue Code.
The IRS defines negligence broadly. It includes any failure to make a reasonable attempt to comply with the tax laws, any failure to keep adequate books and records, any failure to substantiate items properly, and any careless, reckless, or intentional disregard of rules and regulations. The core question the IRS asks is: did the taxpayer exercise the level of care that a reasonable and ordinarily prudent person would exercise under the same circumstances? If the answer is no — and the failure results in an underpayment — the negligence penalty applies.
20% Penalty Rate
Added to the portion of underpayment attributable to negligence — applied on top of the tax owed plus interest.
Reasonable Attempt Standard
The IRS asks whether you made a reasonable effort — not whether the error was intentional or accidental.
Adequate Records Required
Failure to keep proper books and records is one of the most common negligence triggers.
Defenses Exist
Reasonable cause, good faith, and reliance on a tax professional can defeat a negligence penalty.
What the IRS Looks At
When evaluating whether the negligence penalty applies, the IRS examines specific factors in your tax history and recordkeeping practices.
Did You Keep Proper Books and Records?
The IRS expects taxpayers to maintain records sufficient to establish the correct amount of income, deductions, credits, and other items reported on a return. This means: a system for tracking income (bank statements, invoices, 1099s), receipts and logs for deductions, and contemporaneous records created at or near the time of each transaction. Bank statements alone — without supporting detail — are generally insufficient for substantial deductions. The IRS will ask: if you were audited tomorrow, could you produce documentation for every significant line item on your return? If not, you may be found negligent even if the numbers are approximately right.
Did You Make a Reasonable Effort to Determine the Correct Tax Treatment?
Taxpayers are expected to exercise reasonable diligence in determining their tax obligations. This does not mean you need to be a tax expert — the standard is what a reasonable person would do. For a straightforward W-2 return, a reasonable effort may be minimal. For a return with a Schedule C business, rental properties, foreign accounts, cryptocurrency transactions, or complex investment activity, the standard is higher. The IRS will look at whether you researched the tax treatment, consulted IRS publications, sought professional advice, or simply guessed. Claiming a deduction or credit without any effort to verify eligibility is a hallmark of negligence.
Did You Rely on Professional Advice — and Was That Reliance Reasonable?
Reliance on the advice of a competent tax professional (CPA, Enrolled Agent, or tax attorney) is one of the strongest defenses to the negligence penalty — but the reliance must be reasonable. The IRS evaluates three things: (1) Was the advisor competent and experienced in the relevant area of tax law? A general business advisor or bookkeeper who is not a tax professional does not qualify. (2) Did you provide the advisor with complete and accurate information? If you withheld information, gave partial facts, or failed to disclose a transaction, the defense fails. (3) Did the advisor actually provide specific advice about the item in question? A general statement that 'your return looks fine' is insufficient — the advisor must have specifically considered and advised on the tax treatment of the disputed item. Written advice is significantly stronger than oral advice.
Did You Carelessly, Recklessly, or Intentionally Disregard Rules and Regulations?
Disregard of rules and regulations is a separate ground from negligence under IRC §6662(c), though both trigger the same 20% penalty. Careless disregard means you simply did not check or consider the rules. Reckless disregard means you knew (or should have known) about the rules but proceeded anyway with little or no effort to comply. Intentional disregard means you knew the rules and chose to ignore them — this borders on civil fraud and can make the 75% fraud penalty a live issue. The IRS looks at whether you ignored IRS notices, disregarded clear IRS guidance, or took a position for which there is no reasonable basis in law.
How the 20% Penalty Is Calculated
Understanding exactly how the penalty is computed — and how it interacts with interest and other penalties — is essential to evaluating your exposure.
The negligence penalty is 20% of the portion of the underpayment attributable to negligence. This is critical: the penalty applies only to the underpayment amount, not to the total tax liability. If your return showed a tax of $15,000 but the correct tax was $20,000, the underpayment is $5,000. If the entire $5,000 underpayment is attributable to negligence, the penalty is $1,000 (20% of $5,000). If only $2,000 of the underpayment is from negligence and the rest is from a different error with a reasonable basis, the penalty is $400 (20% of $2,000).
The penalty is assessed in addition to the tax owed, and interest compounds on both the tax and the penalty from the original due date of the return. On a $5,000 underpayment from a return due three years ago, the 20% penalty adds $1,000, and interest (at the IRS underpayment rate, which adjusts quarterly) could add hundreds more. The total cost can easily exceed 30-40% of the original underpayment once interest is included.
| Scenario | Underpayment | Penalty (20%) | Est. Interest (3 yrs) | Total Owed |
|---|---|---|---|---|
| Small error — unreported 1099 income | $2,000 | $400 | $420 | $2,820 |
| Moderate — unsubstantiated deductions | $8,000 | $1,600 | $1,680 | $11,280 |
| Significant — Schedule C errors | $25,000 | $5,000 | $5,250 | $35,250 |
| Major — multiple issues across returns | $75,000 | $15,000 | $15,750 | $105,750 |
* Estimated interest based on an average 7% annual underpayment rate compounded daily over 3 years. Actual rates vary quarterly.
Penalty Stacking Rule
The accuracy-related penalty (which includes negligence) cannot be stacked with the civil fraud penalty on the same underpayment portion. If the IRS asserts both negligence and fraud on the same amount, only the higher penalty applies. However, the IRS can assert a negligence penalty on one portion of an underpayment and a fraud penalty on another. Additionally, the failure-to-file and failure-to-pay penalties operate independently — they are not subject to the same stacking rule and can accumulate alongside an accuracy-related penalty.
Negligence vs. Disregard of Rules and Regulations
IRC §6662(c) identifies two distinct grounds for the accuracy-related penalty. Understanding the difference matters for your defense.
Negligence
Negligence is defined as any failure to make a reasonable attempt to comply with the provisions of the Internal Revenue Code. The term includes:
- Failure to keep adequate books and records
- Failure to substantiate items properly (no receipts, logs, or supporting documentation)
- Failure to report income clearly shown on information returns (W-2s, 1099s)
- Claiming deductions or credits without a reasonable basis in fact or law
Negligence is a passive failure — it does not require intent, knowledge, or even awareness. You can be negligent simply by not doing what a reasonable person would do.
Disregard of Rules and Regulations
Disregard of rules and regulations is a more active form of noncompliance. It includes:
- Careless disregard: insufficient effort to learn or follow the applicable rules
- Reckless disregard: knew or should have known the rules but proceeded with little effort to comply
- Intentional disregard: knew the rules and chose to ignore them — can overlap with civil fraud
- Taking a return position contrary to a Treasury Regulation or IRS Revenue Ruling
Disregard is an active failure — it involves a conscious (or consciously indifferent) decision to ignore established rules, not just an oversight or mistake.
How to Defeat a Negligence Penalty
The negligence penalty is not automatic or mandatory — the IRS must prove negligence, and strong defenses can prevent or remove the penalty entirely.
01. Reasonable Cause and Good Faith
The most fundamental defense to the negligence penalty is demonstrating reasonable cause and good faith. Under Treas. Reg. § 1.6664-4, the accuracy-related penalty does not apply to any portion of an underpayment if the taxpayer acted with reasonable cause and in good faith. This is a facts-and-circumstances test — the IRS considers: the taxpayer's efforts to assess their proper tax liability, the taxpayer's experience, knowledge, and education, and the extent to which the taxpayer relied on professional advice. The key is showing you made a genuine, good-faith effort to comply — not a perfect effort, but a reasonable one.
02. Reliance on a Competent Tax Professional
Reliance on the advice of a CPA, Enrolled Agent, or tax attorney is one of the strongest specific defenses to the negligence penalty. To succeed, you must show: (1) the advisor was a competent professional with expertise in the relevant area of tax law — a general bookkeeper, financial planner, or family member does not qualify; (2) you provided the advisor with all relevant facts and accurate information — if you withheld documents, misrepresented facts, or failed to disclose key information, the defense fails; (3) the advisor actually examined the tax treatment of the specific item in question and provided advice on it — a general review or a statement that your return 'looks okay' is insufficient; and (4) your reliance was objectively reasonable — the advisor's advice must have been within their area of competence and not obviously wrong. Written advice is far stronger than oral advice. If your CPA gave you a written memo or email specifically addressing the tax treatment of the item the IRS is now challenging, present it.
03. Adequate Books and Records — the Error Was an Honest Mistake
The IRS's negligence determination often turns on recordkeeping. If you maintained adequate books and records — a reasonable accounting system, contemporaneous records, supporting documentation for major items — but made a technical error in applying the tax law, that is more likely to be treated as an honest mistake rather than negligence. The fact that you have records (even if they don't perfectly prove every item) shows the IRS that you made an effort to comply. Conversely, the absence of records — or records that were clearly created after the fact — strongly supports a negligence finding. If you are being audited and do not have records, begin reconstruction immediately from bank statements, vendor records, client records, and any other third-party sources. Demonstrate effort.
04. The IRS Cannot Prove Negligence for the Specific Underpayment
The IRS bears the burden of production for the negligence penalty — meaning the IRS must come forward with sufficient evidence that the penalty is appropriate. If the IRS cannot identify specific facts showing that your conduct was negligent, the penalty should not be sustained. This is particularly relevant when the underpayment is due to a legal dispute rather than a factual one — for example, if you took a tax position that the IRS disagrees with but that position had a reasonable basis in law. Disagreement with the IRS is not the same as negligence. If you had a colorable legal argument for your tax treatment — even if the IRS ultimately prevails on the substantive issue — you may defeat the negligence penalty on the grounds that your conduct was reasonable.
05. Substantial Authority for Your Tax Position
Under IRC §6662(d)(2)(B)(i), the substantial understatement penalty (another branch of the accuracy-related penalty) is reduced to the extent the taxpayer had substantial authority for the tax treatment of an item, or adequately disclosed the item on the return and had a reasonable basis for the treatment. While this is technically a defense to the substantial understatement penalty rather than the negligence penalty, it overlaps significantly: demonstrating substantial authority for your position makes it much harder for the IRS to claim you were negligent. Substantial authority means the weight of authorities supporting your position is substantial relative to the weight of authorities supporting the contrary treatment — you do not need to prove that your position is more likely than not correct, only that it has substantial legal support.
How to Challenge a Negligence Penalty
The approach you take depends on where you are in the IRS process — before assessment, after assessment, or on appeal.
Before Assessment
- Present your documentation to the auditor during the examination
- Demonstrate your recordkeeping system and any professional advice received
- Raise reasonable cause arguments before the Revenue Agent Report (RAR) is issued
- If the auditor proposes the penalty, request a conference with the auditor's manager
- Provide a written protest with legal analysis citing Treasury Regulations
Post-Assessment
- File Form 843 (Claim for Refund and Request for Abatement) with supporting documentation
- Include a written statement detailing your reasonable cause defense
- Attach all evidence: professional advice letters, records, contemporaneous documentation
- If denied, request an Appeals conference within 30 days
- You may also request audit reconsideration to reopen the underlying examination
Formal Appeal
- File a formal written protest with IRS Independent Office of Appeals
- Raise both factual defenses (adequate records, reasonable cause) and legal defenses (substantial authority)
- Present your case at an Appeals conference — either in person, by phone, or by correspondence
- Appeals Officers have broad authority to settle cases based on hazards of litigation
- If Appeals sustains the penalty, you may petition the U.S. Tax Court
What Are Adequate Records?
The single most common trigger for a negligence penalty is inadequate recordkeeping. Here is what the IRS expects.
Income Records
- Bank statements showing all deposits
- W-2s and 1099s (NEC, MISC, INT, DIV, B, R, K)
- Invoices issued to clients or customers
- Settlement statements for real estate or securities sales (Form 1099-S, 1099-B)
- Records of cash transactions
- Business receipts and daily sales logs (Z-tapes, POS reports)
- Schedule K-1 from partnerships, S corporations, trusts, and estates
Deduction Records
- Receipts showing date, amount, payee, and business purpose
- Canceled checks and credit card statements (but these alone are not enough — you need the receipt or invoice showing what was purchased)
- Mileage logs with date, destination, purpose, and odometer readings
- Travel records: transportation tickets, hotel folios, meal receipts with business purpose notations
- Home office: floor plan, square footage calculation, utility bills
- Asset purchase records: invoices, depreciation schedules, date placed in service
Business Records
- General ledger or accounting system (QuickBooks, Xero, or equivalent)
- Bank account and credit card statements reconciled to your books
- Payroll records: Forms 941, W-2s, W-3s, state payroll tax returns
- Inventory records: physical counts, costing records
- Contracts and agreements with clients, vendors, and employees
- Minutes of board meetings for corporations
- Business licenses, permits, and professional credentials
Retention Requirements
- Keep records for at least 3 years from the date you filed your return
- Keep records for 6 years if you underreported income by more than 25%
- Keep records for 7 years if you claimed a loss from worthless securities or bad debt deduction
- Keep records indefinitely if you filed a fraudulent return or did not file a return at all
- Keep employment tax records for at least 4 years after the tax was due or paid (whichever is later)
- Keep asset records for as long as you own the asset plus the retention period after you dispose of it (for depreciation recapture and capital gain calculation)
Critical: Contemporaneous Records
The IRS distinguishes between contemporaneous records (created at or near the time of the transaction) and reconstructed records (created after the fact). Contemporaneous records carry significantly more weight in a negligence determination. A mileage log maintained daily throughout the year is strong evidence; a mileage log reconstructed in a single sitting the night before an audit meeting is weak evidence and may actually support a negligence finding. If you do not have contemporaneous records, begin reconstruction immediately — but be transparent with the IRS about what was contemporaneous and what is reconstructed.
Reliance on a Tax Professional: When It Works
This is the single most effective defense against the negligence penalty — but it must be done correctly.
The Advisor Must Be a Qualified Tax Professional
The IRS applies a competence standard. A CPA, Enrolled Agent (EA), or tax attorney who regularly prepares returns and has expertise in the relevant area of tax law qualifies. A general bookkeeper, a financial planner who does not hold a tax credential, a family member, or a friend — even if they have been filing returns for years — generally does not. The question is not whether the person is smart or honest, but whether they have the professional tax expertise necessary to provide competent advice. If you used a CPA who specializes in the area at issue (e.g., a CPA who handles real estate taxation for a §1031 exchange question), the defense is strongest.
You Must Provide Complete and Accurate Information
The reliance defense requires that you gave the advisor all the facts. If you failed to disclose a source of income, provided incomplete bank statements, or omitted transactions, the defense fails — even if the advisor was otherwise competent and you otherwise acted in good faith. The IRS will ask: did the advisor have everything they needed to give correct advice? If the answer is no, the negligence penalty will likely stand. This is why organized, complete records are not just an IRS requirement — they are essential to preserving your professional-reliance defense.
The Advice Must Address the Specific Tax Treatment at Issue
A general statement from your CPA that 'your return looks correct' is not enough. The advisor must have actually examined and advised on the specific item that is the subject of the negligence penalty. For example: if the IRS says you were negligent in deducting certain expenses, you need to show the advisor specifically reviewed those expenses and advised that they were deductible. A written memo, email, or engagement letter in which the advisor specifically addresses the tax treatment of the item is gold — it is the strongest possible evidence of reasonable reliance.
The Reliance Must Be Objectively Reasonable
Even if your CPA gave you specific written advice, the reliance defense fails if the advice was obviously wrong. For example, if your CPA told you that you don't need to report any income below $20,000 — that advice is so clearly inconsistent with the Internal Revenue Code that relying on it is not reasonable. The standard is objective: would a reasonable person in your position have relied on that advice? This prevents taxpayers from using a 'yes-man' advisor who tells them what they want to hear as a shield against penalties.
Fight Your Negligence Penalty Today
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