Treasury Regulations · 26 CFR
§ 1.6664-3. Ordering rules for determining the total amount of penalties imposed.
Regulation text, no changes From the eCFR, current as of October 15, 2026. The eCFR is an authoritative but unofficial editorial compilation of the Code of Federal Regulations; the official text is the annual CFR on govinfo. Compare it with this section on ecfr.gov (external site) or the official annual CFR on govinfo (external site).
Regulation under 26 U.S.C. § 6664
Cite as 26 CFR § 1.6664-3
At a glance
Read from the text and its source citation. Not part of the regulation.
- Status
- In the current eCFR
- Issued
- December 31, 1991 by T.D. 8381
- Last amended
- February 20, 1992 by T.D. 8381
- Issued under
- 26 U.S.C. § 6664
- Length
- 949 words · about 4 min to read
- Cross-references
- cites 2 Code sections and 1 regulation; cited by 2
This section also provides rules for allocating unclaimed prepayment credits to adjustments to a return.
A and B, husband and wife, filed a joint federal income tax return for calendar year 1989, reporting taxable income of $15,800 and a tax liability of $2,374. A and B had no amounts previously assessed (or collected without assessment) and no rebates had been made. Subsequently, the return was examined and the following adjustments and penalties were agreed to:
| Adjustment #1 (No penalty imposed) | $1,000 | |
| Adjustment #2 (Substantial understatement penalty imposed) | 40,000 | |
| Adjustment #3 (Civil fraud penalty imposed) | 45,000 | |
| Total adjustments | $86,000 | |
| Taxable income shown on return | 15,800 | |
| Taxable income as corrected | $101,800 | |
| Computation of underpayment: | ||
| Tax imposed by subtitle A | $25,828 | |
| Tax shown on return | $2,374 | |
| Previous assessments | None | |
| Rebates | None | |
| Balance | $2,374 | |
| Underpayment | $23,454 |
Computation of the portions of the underpayment on which penalties under section 6662(b)(2) and section 6663 are imposed:
Step 1 Determine the portion, if any, of the underpayment on which no accuracy-related or fraud penalty is imposed:
| Taxable income shown on return | $15,800 |
| Adjustment #1 | 1,000 |
| “Adjusted” taxable income | $16,800 |
| Tax on “adjusted” taxable income | $2,524 |
| Tax shown on return | 2,374 |
| Portion of underpayment on which no penalty is imposed | $150 |
Step 2 Determine the portion, if any, of the underpayment on which a penalty of 20 percent is imposed:
| “Adjusted” taxable income from step 1 | $16,800 |
| Adjustment #2 | 40,000 |
| “Adjusted” taxable income | 56,800 |
| Tax on “adjusted” taxable income | $11,880 |
| Tax on “adjusted” taxable income from step 1 | $2,524 |
| Portion of underpayment on which 20 percent penalty is imposed | $9,356 |
Step 3 Determine the portion, if any, of the underpayment on which a penalty of 75 percent is imposed:
| Total underpayment | $23,454 | |
| Less the sum of the portions of such underpayment determined in: | ||
| Step 1 | $150 | |
| Step 2 | 9,356 | |
| Total | $9,506 | |
| Portion of underpayment on which 75 percent penalty is imposed | $13,948 |
The facts are the same as in Example 1 except that the taxpayers failed to claim on their return a credit of $1,500 for income tax withheld on unreported additional income that resulted in Adjustment #2. Because the unclaimed prepayment credit is allocable to Adjustment #2, the portion of the underpayment attributable to that adjustment is $7,856 ($9,356—$1,500). The portions of the underpayment attributable to Adjustments #1 and #3 remain the same.
The facts are the same as in Example 1 except that the taxpayers made a timely estimated tax payment of $1,500 for 1989 which they failed to claim (and which the Service had not previously allowed). This unclaimed prepayment credit is not allocable to any particular adjustment. Therefore, the credit is allocated first to the portion of the underpayment on which no penalty is imposed ($150). The remaining amount ($1,350) is allocated next to the 20 percent penalty portion of the underpayment ($9,356). Thus, the portion of the underpayment that is not penalized is zero ($150—$150), the portion subject to a 20 percent penalty is $8,006 ($9,356—$1,350) and the portion subject to a 75 percent penalty is unchanged at $13,948.
[T.D. 8381, 56 FR 67507, Dec. 31, 1991; T.D. 8381, 57 FR 6165, Feb. 20, 1992]
Cross-references
Computed from the citations in the text of 26 CFR.
Code sections it cites
Regulations it cites
Cited by 2 other regulations
Amendment history
From the source citation at the end of the section, newest first. T.D. is a Treasury decision; FR is the Federal Register.
- Amended by T.D. 8381 (57 FR 6165)
- Issued by T.D. 8381 (56 FR 67507)
Where it sits in 26 CFR
- Subchapter A Income tax
- Part 1 Income taxes
- Additions to the tax, additional amounts, and assessable penalties
Nearby sections
- § 1.6662-9 Inconsistent estate basis reporting.
- § 1.6664-0 Table of contents.
- § 1.6664-1 Accuracy-related and fraud penalties; definitions, effective date and special rules.
- § 1.6664-2 Underpayment.
- § 1.6664-3 Ordering rules for determining the total amount of penalties imposed.
- § 1.6664-4 Reasonable cause and good faith exception to section 6662 penalties.
- § 1.6664-4T Reasonable cause and good faith exception to section 6662 penalties.
- § 1.6694-0 Table of contents.
- § 1.6694-1 Section 6694 penalties applicable to tax return preparers.