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)

Fourth Quarter 2021

3.25% Dec     .0028 .0027
   

Nov     .0027

 
   

Oct      .0028

 

Third Quarter 2021

3.25%

Sep      .0027

.0027
    Aug     .0028  
    Jul       .0028  

Second Quarter 2021

3.25% Jun .0027 .0027
   

May  .0028

 
   

Apr .0027

 

First Quarter 2021

3.25%

Mar .0028

.0027

   

Feb  .0025

 
   

Jan .0028

 

Fourth Quarter 2020

3.25%

Dec .0028

.0027

   

Nov .0027

 
   

Oct .0028

 

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

 
   

Oct .0042

 

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 September 15, 2021