Revenue Ruling 2023-4
Internal Revenue Service
2023-9 I.R.B. 480
   
   
   
 Section 6621.--Determination of Rate of Interest      
     
 26 CFR 301.6621-1: Interest rate.      
     
 Rev. Rul. 2023-4      
     
Section 6621 of the Internal Revenue Code establishes the interest rates on overpayments and underpayments of tax. 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. 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 that month. Section 6621(b)(3) provides that the federal short-term rate for any month is the federal short-term rate determined during that month by the Secretary in accordance with section 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.   
     
The federal short-term rate determined in accordance with section 1274(d) during January 2023 is the rate published in Revenue Ruling 2023-3, 2023-6 IRB 448, to take effect beginning February 1, 2023. The federal short-term rate, rounded to the nearest full percent, based on daily compounding determined during the month of January 2023 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 April 1, 2023. The overpayment rate for the portion of a corporate overpayment exceeding $10,000 for the calendar quarter beginning April 1, 2023, is 4.5 percent. The underpayment rate for large corporate underpayments for the calendar quarter beginning April 1, 2023, is 9 percent. These rates apply to amounts bearing interest during that calendar quarter.   
     
Sections 6654(a)(1) and 6655(a)(1) provide that the underpayment rate established under section 6621 applies in determining the addition to tax under sections 6654 and 6655 for failure to pay estimated tax for any taxable year. Thus, the 7 percent rate also applies to estimated tax underpayments for the second calendar quarter beginning April 1, 2023. Pursuant to section 6621(b)(2)(B), in determining the addition to tax under section 6654 for any taxable year for an individual, the federal short-term rate that applies during the third month following the taxable year also applies during the first 15 days of the fourth month following the taxable year. See Rev. Rul. 2022-23, 2022-51 IRB 532 (7 percent rate for the first quarter of 2023). In addition, pursuant to section 6603(d)(4), the rate of interest on section 6603 deposits is 4 percent for the second calendar quarter in 2023.   
     
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. 95-17, 1995-1 C.B. 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 Casey R. Conrad of the Office of the Associate Chief Counsel (Procedure and Administration). For further information regarding this revenue ruling, contact Mr. Conrad at (202) 317-6844 (not a toll-free number).