Introduction›Part I. Rulings and Decisions Under the Internal Revenue Code of 1986
Section 6621.—Determina- tion of Rate of Interest
Internal Revenue Bulletin 2005-38 · 2026-10-03 edition · updated 2026-10-04 · United States
26 CFR 301.6621–1: Interest rate.
Interest rates; underpayments and overpayments. The rate of interest determined under section 6621 of the Code for the calendar quarter beginning October 1, 2005, will be 7 percent for overpayments (6 percent in the case of a corporation), 7 percent for underpayments, and 9 percent for large corporate underpayments. The rate of interest paid on the portion of a corporate overpayment exceeding $10,000 will be 4.5 percent.
Rev. Rul. 2005–62
Section 6621 of the Internal Revenue Code establishes the rates for interest on tax overpayments and tax underpayments. Under section 6621(a)(1), the overpayment rate is the sum of the federal short-term rate plus 3 percentage points (2 percentage points in the case of a corporation), except the rate for the portion of a corporate overpayment of tax exceeding $10,000 for a taxable period is the sum of the federal short-term rate plus 0.5 of a percentage point for interest computations made after December 31, 1994. Under section 6621(a)(2), the underpayment rate is the sum of the federal short-term rate plus 3 percentage points.
Section 6621(c) provides that for purposes of interest payable under section 6601 on any large corporate underpayment, the underpayment rate under section 6621(a)(2) is determined by substituting “5 percentage points” for “3 percentage points.” See section 6621(c) and section 301.6621–3 of the Regulations on Procedure and Administration for the definition of a large corporate underpayment and for the rules for determining the applicable date. Section 6621(c) and section 301.6621–3 are generally effective for periods after December 31, 1990.
Section 6621(b)(1) provides that the Secretary will determine the federal short-term rate for the first month in each calendar quarter.
Section 6621(b)(2)(A) provides that the federal short-term rate determined under section 6621(b)(1) for any month applies during the first calendar quarter beginning after such month.
September 19, 2005 557 2005–38 I.R.B.
95–17, 1995–1 C.B. 556, 568, 571, 573, and 577.
Annual interest rates to be compounded daily pursuant to section 6622 that apply for prior periods are set forth in the tables accompanying this revenue ruling.
DRAFTING INFORMATION
The principal author of this revenue ruling is Crystal Foster of the Office of Associate Chief Counsel (Procedure & Administration). For further information regarding this revenue ruling, contact Ms. Foster at (202) 622–7198 (not a toll-free call).
Section 6621(b)(3) provides that the federal short-term rate for any month is the federal short-term rate determined during such month by the Secretary in accordance with § 1274(d), rounded to the nearest full percent (or, if a multiple of 1 /2 of 1 percent, the rate is increased to the next highest full percent).
Notice 88–59, 1988–1 C.B. 546, announced that, in determining the quarterly interest rates to be used for overpayments and underpayments of tax under section 6621, the Internal Revenue Service will use the federal short-term rate based on daily compounding because that rate is most consistent with section 6621 which, pursuant to section 6622, is subject to daily compounding.
Rounded to the nearest full percent, the federal short-term rate based on daily com
pounding determined during the month of July 2005 is 4 percent. Accordingly, an overpayment rate of 7 percent (6 percent in the case of a corporation) and an underpayment rate of 7 percent are established for the calendar quarter beginning October 1, 2005. The overpayment rate for the portion of a corporate overpayment exceeding $10,000 for the calendar quarter beginning October 1, 2005, is 4.5 percent. The underpayment rate for large corporate underpayments for the calendar quarter beginning October 1, 2005, is 9 percent. These rates apply to amounts bearing interest during that calendar quarter.
Interest factors for daily compound interest for annual rates of 4.5 percent, 6 percent, 7 percent, and 9 percent are published in Tables 14, 17, 19, and 23 of Rev. Proc.
TABLE OF INTEREST RATES
PERIODS BEFORE JUL. 1, 1975 - PERIODS ENDING DEC. 31, 1986
OVERPAYMENTS AND UNDERPAYMENTS
PERIOD RATE
In 1995–1 C.B. DAILY RATE TABLE
Before Jul. 1, 1975 6% Table 2, pg. 557 Jul. 1, 1975—Jan. 31, 1976 9% Table 4, pg. 559 Feb. 1, 1976—Jan. 31, 1978 7% Table 3, pg. 558 Feb. 1, 1978—Jan. 31, 1980 6% Table 2, pg. 557 Feb. 1, 1980—Jan. 31, 1982 12% Table 5, pg. 560 Feb. 1, 1982—Dec. 31, 1982 20% Table 6, pg. 560 Jan. 1, 1983—Jun. 30, 1983 16% Table 37, pg. 591 Jul. 1, 1983—Dec. 31, 1983 11% Table 27, pg. 581 Jan. 1, 1984—Jun. 30, 1984 11% Table 75, pg. 629 Jul. 1, 1984—Dec. 31, 1984 11% Table 75, pg. 629 Jan. 1, 1985—Jun. 30, 1985 13% Table 31, pg. 585 Jul. 1, 1985—Dec. 31, 1985 11% Table 27, pg. 581 Jan. 1, 1986—Jun. 30, 1986 10% Table 25, pg. 579 Jul. 1, 1986—Dec. 31, 1986 9% Table 23, pg. 577
2005–38 I.R.B. 558 September 19, 2005
September 19, 2005 559 2005–38 I.R.B.
TABLE OF INTEREST RATES
FROM JANUARY 1, 1999 - PRESENT
NONCORPORATE OVERPAYMENTS AND UNDERPAYMENTS
1995–1 C.B. RATE TABLE PG
Jan. 1, 1999—Mar. 31, 1999 7% 19 573 Apr. 1, 1999—Jun. 30, 1999 8% 21 575 Jul. 1, 1999—Sep. 30, 1999 8% 21 575 Oct. 1, 1999—Dec. 31, 1999 8% 21 575 Jan. 1, 2000—Mar. 31, 2000 8% 69 623 Apr. 1, 2000—Jun. 30, 2000 9% 71 625 Jul. 1, 2000—Sep. 30, 2000 9% 71 625 Oct. 1, 2000—Dec. 31, 2000 9% 71 625 Jan. 1, 2001—Mar. 31, 2001 9% 23 577 Apr. 1, 2001—Jun. 30, 2001 8% 21 575 Jul. 1, 2001—Sep. 30, 2001 7% 19 573 Oct. 1, 2001—Dec. 31, 2001 7% 19 573 Jan. 1, 2002—Mar. 31, 2002 6% 17 571 Apr. 1, 2002—Jun. 30, 2002 6% 17 571 Jul. 1, 2002—Sep. 30, 2002 6% 17 571 Oct. 1, 2002—Dec. 31, 2002 6% 17 571 Jan. 1, 2003—Mar. 31, 2003 5% 15 569 Apr. 1, 2003—Jun. 30, 2003 5% 15 569 Jul. 1, 2003—Sep. 30, 2003 5% 15 569 Oct. 1, 2003—Dec. 31, 2003 4% 13 567 Jan. 1, 2004—Mar. 31, 2004 4% 61 615 Apr. 1, 2004—Jun. 30, 2004 5% 63 617 Jul. 1, 2004—Sep. 30, 2004 4% 61 615 Oct. 1, 2004—Dec. 31, 2004 5% 63 617 Jan. 1, 2005—Mar. 31, 2005 5% 15 569 Apr. 1, 2005—Jun. 30, 2005 6% 17 571 Jul. 1, 2005—Sep. 30, 2005 6% 17 571 Oct. 1, 2005—Dec. 31, 2005 7% 19 573
2005–38 I.R.B. 560 September 19, 2005
TABLE OF INTEREST RATES FOR LARGE CORPORATE UNDERPAYMENTS
FROM JANUARY 1, 1991 - PRESENT
1995–1 C.B. RATE TABLE PG
Jan. 1, 1991—Mar. 31, 1991 13% 31 585 Apr. 1, 1991—Jun. 30, 1991 12% 29 583 Jul. 1, 1991—Sep. 30, 1991 12% 29 583 Oct. 1, 1991—Dec. 31, 1991 12% 29 583 Jan. 1, 1992—Mar. 31, 1992 11% 75 629 Apr. 1, 1992—Jun. 30, 1992 10% 73 627 Jul. 1, 1992—Sep. 30, 1992 10% 73 627 Oct. 1, 1992—Dec. 31, 1992 9% 71 625 Jan. 1, 1993—Mar. 31, 1993 9% 23 577 Apr. 1, 1993—Jun. 30, 1993 9% 23 577 Jul. 1, 1993—Sep. 30, 1993 9% 23 577 Oct. 1, 1993—Dec. 31, 1993 9% 23 577 Jan. 1, 1994—Mar. 31, 1994 9% 23 577 Apr. 1, 1994—Jun. 30, 1994 9% 23 577 Jul. 1, 1994—Sep. 30, 1994 10% 25 579 Oct. 1, 1994—Dec. 31, 1994 11% 27 581 Jan. 1, 1995—Mar. 31, 1995 11% 27 581 Apr. 1, 1995—Jun. 30, 1995 12% 29 583 Jul. 1, 1995—Sep. 30, 1995 11% 27 581 Oct. 1, 1995—Dec. 31, 1995 11% 27 581 Jan. 1, 1996—Mar. 31, 1996 11% 75 629 Apr. 1, 1996—Jun. 30, 1996 10% 73 627 Jul. 1, 1996—Sep. 30, 1996 11% 75 629 Oct. 1, 1996—Dec. 31, 1996 11% 75 629 Jan. 1, 1997—Mar. 31, 1997 11% 27 581 Apr. 1, 1997—Jun. 30, 1997 11% 27 581 Jul. 1, 1997—Sep. 30, 1997 11% 27 581 Oct. 1, 1997—Dec. 31, 1997 11% 27 581 Jan. 1, 1998—Mar. 31, 1998 11% 27 581 Apr. 1, 1998—Jun. 30, 1998 10% 25 579 Jul. 1, 1998—Sep. 30, 1998 10% 25 579 Oct. 1, 1998—Dec. 31, 1998 10% 25 579 Jan. 1, 1999—Mar. 31, 1999 9% 23 577
September 19, 2005 561 2005–38 I.R.B.
TABLE OF INTEREST RATES FOR LARGE CORPORATE UNDERPAYMENTS
FROM JANUARY 1, 1991 - PRESENT - Continued
1995–1 C.B. RATE TABLE PG
Apr. 1, 1999—Jun. 30, 1999 10% 25 579 Jul. 1, 1999—Sep. 30, 1999 10% 25 579 Oct. 1, 1999—Dec. 31, 1999 10% 25 579 Jan. 1, 2000—Mar. 31, 2000 10% 73 627 Apr. 1, 2000—Jun. 30, 2000 11% 75 629 Jul. 1, 2000—Sep. 30, 2000 11% 75 629 Oct. 1, 2000—Dec. 31, 2000 11% 75 629 Jan. 1, 2001—Mar. 31, 2001 11% 27 581 Apr. 1, 2001—Jun. 30, 2001 10% 25 579 Jul. 1, 2001—Sep. 30, 2001 9% 23 577 Oct. 1, 2001—Dec. 31, 2001 9% 23 577 Jan. 1, 2002—Mar. 31, 2002 8% 21 575 Apr. 1, 2002—Jun. 30, 2002 8% 21 575 Jul. 1, 2002—Sep. 30, 2002 8% 21 575 Oct. 1, 2002—Dec. 30, 2002 8% 21 575 Jan. 1, 2003—Mar. 31, 2003 7% 19 573 Apr. 1, 2003—Jun. 30, 2003 7% 19 573 Jul. 1, 2003—Sep. 30, 2003 7% 19 573 Oct. 1, 2003—Dec. 31, 2003 6% 17 571 Jan. 1, 2004—Mar. 31, 2004 6% 65 619 Apr. 1, 2004—Jun. 30, 2004 7% 67 621 Jul. 1, 2004—Sep. 30, 2004 6% 65 619 Oct. 1, 2004—Dec. 31, 2004 7% 67 621 Jan. 1, 2005—Mar. 31, 2005 7% 19 573 Apr. 1, 2005—Jun. 30, 2005 8% 21 575 Jul. 1, 2005—Sep. 30, 2005 8% 21 575 Oct. 1, 2005—Dec. 31, 2005 9% 23 577
TABLE OF INTEREST RATES FOR CORPORATE
OVERPAYMENTS EXCEEDING $10,000
FROM JANUARY 1, 1995 - PRESENT
1995–1 C.B. RATE TABLE PG
Jan. 1, 1995—Mar. 31, 1995 6.5% 18 572 Apr. 1, 1995—Jun. 30, 1995 7.5% 20 574 Jul. 1, 1995—Sep. 30, 1995 6.5% 18 572 Oct. 1, 1995—Dec. 31, 1995 6.5% 18 572 Jan. 1, 1996—Mar. 31, 1996 6.5% 66 620 Apr. 1, 1996—Jun. 30, 1996 5.5% 64 618 Jul. 1, 1996—Sep. 30, 1996 6.5% 66 620 Oct. 1, 1996—Dec. 31, 1996 6.5% 66 620 Jan. 1, 1997—Mar. 31, 1997 6.5% 18 572 Apr. 1, 1997—Jun. 30, 1997 6.5% 18 572 Jul. 1, 1997—Sep. 30, 1997 6.5% 18 572 Oct. 1, 1997—Dec. 31, 1997 6.5% 18 572 Jan. 1, 1998—Mar. 31, 1998 6.5% 18 572 Apr. 1, 1998—Jun. 30, 1998 5.5% 16 570 Jul. 1, 1998—Sep. 30, 1998 5.5% 16 570 Oct. 1, 1998—Dec. 31, 1998 5.5% 16 570 Jan. 1, 1999—Mar. 31, 1999 4.5% 14 568 Apr. 1, 1999—Jun. 30, 1999 5.5% 16 570 Jul. 1, 1999—Sep. 30, 1999 5.5% 16 570
2005–38 I.R.B. 562 September 19, 2005
TABLE OF INTEREST RATES FOR CORPORATE
OVERPAYMENTS EXCEEDING $10,000
FROM JANUARY 1, 1995 - PRESENT - Continued
1995–1 C.B. RATE TABLE PG
Oct. 1, 1999—Dec. 31, 1999 5.5% 16 570 Jan. 1, 2000—Mar. 31, 2000 5.5% 64 618 Apr. 1, 2000—Jun. 30, 2000 6.5% 66 620 Jul. 1, 2000—Sep. 30, 2000 6.5% 66 620 Oct. 1, 2000—Dec. 31, 2000 6.5% 66 620 Jan. 1, 2001—Mar. 31, 2001 6.5% 18 572 Apr. 1, 2001—Jun. 30, 2001 5.5% 16 570 Jul. 1, 2001—Sep. 30, 2001 4.5% 14 568 Oct. 1, 2001—Dec. 31, 2001 4.5% 14 568 Jan. 1, 2002—Mar. 31, 2002 3.5% 12 566 Apr. 1, 2002—Jun. 30, 2002 3.5% 12 566 Jul. 1, 2002—Sep. 30, 2002 3.5% 12 566 Oct. 1, 2002—Dec. 31, 2002 3.5% 12 566 Jan. 1, 2003—Mar. 31, 2003 2.5% 10 564 Apr. 1, 2003—Jun. 30, 2003 2.5% 10 564 Jul. 1, 2003—Sep. 30, 2003 2.5% 10 564 Oct. 1, 2003—Dec. 31, 2003 1.5% 8 562 Jan. 1, 2004—Mar. 31, 2004 1.5% 56 610 Apr. 1, 2004—Jun. 30, 2004 2.5% 58 612 Jul. 1, 2004—Sep. 30, 2004 1.5% 56 610 Oct. 1, 2004—Dec. 31, 2004 2.5% 58 612 Jan. 1, 2005—Mar. 31, 2005 2.5% 10 564 Apr. 1, 2005—Jun. 30, 2005 3.5% 12 566 Jul. 1, 2005—Sep. 30, 2005 3.5% 12 566 Oct. 1, 2005—Dec. 31, 2005 4.5% 14 568
September 19, 2005 563 2005–38 I.R.B.
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