§ 6621. Determination of rate of interest

2019—Subsec. (c)(2)(A)(i). Pub. L. 116–25 substituted “Internal Revenue Service Independent Office of Appeals” for “Internal Revenue Service Office of Appeals”.

1998—Subsec. (a)(1)(B). Pub. L. 105–206, § 3302(a), amended subpar. (B) generally. Prior to amendment, subpar. (B) read as follows: “2 percentage points.”

Subsec. (d). Pub. L. 105–206, § 3301(a), added subsec. (d).

1997—Subsec. (a)(1). Pub. L. 105–34, § 1604(b)(1), substituted “subsection (c)(3), applied by substituting ‘overpayment’ for ‘underpayment’)” for “subsection (c)(3))” in concluding provisions.

Subsec. (c)(2)(B)(iii). Pub. L. 105–34, § 1463(a), added cl. (iii).

1996—Subsec. (c)(2)(A). Pub. L. 104–188, § 1702(c)(6), inserted closing provisions “The preceding sentence shall be applied without regard to any such letter or notice which is withdrawn by the Secretary.”

Subsec. (c)(2)(B)(i). Pub. L. 104–188, § 1702(c)(7), substituted “this title” for “this subtitle”.

1994—Subsec. (a)(1). Pub. L. 103–465 inserted concluding provisions.

1990—Subsec. (c). Pub. L. 101–508 added subsec. (c).

1989—Subsec. (c). Pub. L. 101–239 repealed subsec. (c) which related to attribution of interest on substantial underpayments to tax motivated transactions.

1988—Subsec. (a)(1)(A), (2)(A). Pub. L. 100–647, § 1015(d)(1), substituted “Federal short-term” for “short-term Federal”.

Subsec. (b). Pub. L. 100–647, § 1015(d)(2), substituted “Federal short-term” for “short-term Federal” in heading.

Subsec. (b)(1). Pub. L. 100–647, § 1015(d)(1), substituted “Federal short-term” for “short-term Federal”.

1986—Subsec. (a). Pub. L. 99–514, § 1511(a), added subsec. (a) and struck out former subsec. (a) which read as follows: “The annual rate established under this section shall be such adjusted rate as is established by the Secretary under subsection (b).”

Subsec. (b). Pub. L. 99–514, § 1511(a), added subsec. (b) relating to determination of Federal short-term rate and struck out former subsec. (b) which related to interest rate adjustments and establishment of adjusted rates.

Subsec. (c). Pub. L. 99–514, § 1511(a), (c)(1), redesignated subsec. (d) as (c), in par. (1), struck out “annual” before “rate of interest” and substituted “the underpayment rate established under this section” for “the adjusted rate established under subsection (b)”, and struck out former subsec. (c) definition of prime rate, which read as follows: “For purposes of subsection (b), the term ‘adjusted prime rate charged by banks’ means the average predominant prime rate quoted by commercial banks to large businesses, as determined by the Board of Governors of the Federal Reserve System.”

Subsec. (c)(3)(A)(v). Pub. L. 99–514, § 1535(a), added cl. (v).

Subsec. (d). Pub. L. 99–514, § 1511(c)(1)(A), redesignated subsec. (d) as (c).

1984—Subsec. (d). Pub. L. 98–369 added subsec. (d).

1982—Subsec. (b). Pub. L. 97–248 substituted provisions that if the adjusted prime rate charged by banks (rounded to the nearest full percent) during the 6-month period ending on September 30 of any calendar year, or during the 6-month period ending on March 31 of any calendar year, differs from the interest rate in effect under this section on either such date, respectively, then the Secretary shall establish, within 15 days after the close of the applicable 6-month period, an adjusted rate of interest equal to such adjusted prime rate, and that any adjusted rate of interest established under paragraph (1) shall become effective on January 1 of the succeeding year in the case of an adjustment attributable to paragraph (1)(A), and on July 1 of the same year in the case of an adjustment attributable to paragraph (1)(B), for provisions that the Secretary was to establish an adjusted rate of interest for the purpose of subsection (a) not later than October 15 of any year if the adjusted prime rate charged by banks during September of that year, rounded to the nearest full percent, was at least a full percentage point more or less than the interest rate which was then in effect, and that any such adjusted rate of interest would be equal to the adjusted prime rate charged by banks, rounded to the nearest full percent, and would become effective on January 1 of the immediately succeeding year.

1981—Subsec. (b). Pub. L. 97–34, § 711(a), struck out provision that an adjustment provided for under this subsection not be made prior to the expiration of 23 months following the date of any preceding adjustment under this subsection which changes the rate of interest.

Pub. L. 97–34, § 711(c), substituted “January 1” for “February 1”.

Subsec. (c). Pub. L. 97–34, § 711(b), struck out “90 percent of” before “the average predominant prime rate”.

1979—Subsec. (a). Pub. L. 96–167 substituted provisions setting the annual rate established under this section to be such adjusted rate as is established by the Secretary under subsec. (b) of this section for provision that the rate of interest under sections 6601(a), 6602, 6611(a), 6332(c)(1), and 7426(g) of this title, and under section 2411(a) of title 28 was to be 9 percent per annum, or such adjusted rate as was established by the Secretary under subsection (b).

1976—Subsecs. (a), (b). Pub. L. 94–455 struck out “or his delegate” after “Secretary”.

Amendment by section 3301(a) of Pub. L. 105–206 applicable to interest for periods beginning after , and, subject to applicable statutes of limitation, to interest for periods beginning before , if taxpayer reasonably identifies and establishes periods of overpayments and underpayments for which zero rate applies, and not later than , requests application of subsec. (d) of this section to such periods, see section 3301(c) of Pub. L. 105–206, set out as a note under section 6601 of this title.

Amendment by section 1604(b)(1) of Pub. L. 105–34 effective as if included in the sections of the Uruguay Round Agreements Act, Pub. L. 103–465, to which it relates, see section 1604(b)(4) of Pub. L. 105–34, set out as a note under section 412 of this title.

Amendment by Pub. L. 104–188 effective, except as otherwise expressly provided, as if included in the provision of the Revenue Reconciliation Act of 1990, Pub. L. 101–508, title XI, to which such amendment relates, see section 1702(i) of Pub. L. 104–188, set out as a note under section 38 of this title.

Amendment by Pub. L. 101–239 applicable to returns the due date for which (determined without regard to extensions) is after , see section 7721(d) of Pub. L. 101–239, set out as a note under section 461 of this title.

Amendment by Pub. L. 100–647 effective, except as otherwise provided, as if included in the provision of the Tax Reform Act of 1986, Pub. L. 99–514, to which such amendment relates, see section 1019(a) of Pub. L. 100–647, set out as a note under section 1 of this title.

Amendment by section 1511(a), (c)(1) of Pub. L. 99–514 applicable for purposes of determining interest for periods after , see section 1511(d) of Pub. L. 99–514, set out as a note under section 47 of this title.