The Commission, on a quarterly basis, publishes interest rates for oil, natural gas, and electricity for determination of refund purposes. The interest rates on this page as well as the archived rates are the same for oil, natural gas, and electricity. Please note that the interest rates for oil apply only as far back as 1983.

  • Electric Interest Rates are Calculated in Accordance with Section 35.19a of the Commission's regulations. Section 35.19a, subsection (iii)(A) provides that “[t]he applicable average prime rate for each calendar quarter shall be the arithmetic mean, to the nearest one-hundredth of one percent, of the prime rate values published in the Federal Reserve Bulletin, or in the Federal Reserve's “Selected Interest Rates” (Statistical Release H. 15), for the fourth, third, and second months preceding the first month of the calendar quarter.” For example, the refund interest rate for the fourth quarter of a year (October 1 – December 31) would be calculated using the prime rate values published on June 30, July 31 and August 31.
  • Gas Interest Rates are Calculated in Accordance with Section 154.501(d) of the Commission's regulations and its predecessors
  • Oil Interest Rates are Calculated in Accordance with Section 340.1(c)(2) of the Commission's regulations
Applicable Annual Quarter Annual Rate Monthly Rate (Annual % / 365dx # days in month) 1 Monthly Rate (Annual Rate / 12 Months)
Third Quarter 2020 3.43% Sep .0028 .0029
    Aug .0029  
    Jul .0029  
Second Quarter 2020 4.75% Jun .0039 .0040
    May .0040  
    Apr .0039  
First Quarter 2020 4.96% Mar .0042 .0041
    Feb .0039  
    Jan .0042  
Fourth Quarter 2019 5.42% Dec .0046 .0045
    Nov .0045  
    Oct .0046  
Third Quarter 2019 5.50% Sep .0045 .0046
    Aug .0047  
    Jul .0047  
Second Quarter 2019 5.45% Jun .0045 .0045
    May .0046  
    Apr .0045  
First Quarter 2019 5.18% Mar .0044 .0043
    Feb .0040  
    Jan .0044  
Fourth Quarter 2018 4.96% Dec .0042 .0041
    Nov .0041  
Third Quarter 2018 4.69% Sep .0039 .0039
    Aug .0040  
    Jul .0040  
Second Quarter 2018 4.47% Jun .0037 .0037
    May .0038  
    Apr .0037  
First Quarter 2018 4.25% Mar .0036 .0035
    Feb .0033  
    Jan .0036  
Fourth Quarter 2017 4.21% Dec .0036 .0035
    Nov .0035  
    Oct .0036  
Third Quarter 2017 3.96% Sep .0033 .0033
    Aug .0034  
    Jul .0034  
Second Quarter 2017 3.71% Jun .0030 .0031
    May .0032  
    Apr .0030  
First Quarter 2017 3.50% Mar .0030 .0029
    Feb .0027  
    Jan .0030  
Fourth Quarter 2016 3.50% Dec .0030 .0029
    Nov .0029  
    Oct .0030  
Third Quarter 2016 3.50 % Sep .0029 .0029
    Aug .0030  
    Jul .0030  
Second Quarter 2016 3.46%        Jun .0028 .0029
    May .0029  
    Apr .0028  
First Quarter 2016 3.25%        Mar .0028 .0027
    Feb .0026  
    Jan .0028  

This page was last updated on June 22, 2020