Late Payment & Overpayment Interest Tables

The interest rates may be used with the following formula to calculate interest for any period. The formula calculates the interest factor which is then multiplied by the assessment amount to compute the interest due.

For interest owed to ONRR, calculate that interest from the due date of the sales month to the date ONRR received the payment. For interest ONRR owes you, calculate that interest from the due date of the sales month, without regard to an extended due date because of an estimate, to the date ONRR receives Form MMS-2014 recouping the overpayment. The overpayment interest rate is currently one percent less than the underpayment interest rate. Both rates are compounded daily.

COMPOUNDED DAILY INTEREST FORMULA EXAMPLE
USING TWO INTEREST PERIODS

Interest Amount = Assessment amount x ((1 + Annual interest rate/Days per year)     No. of days late  - 1)

Calculate interest on $1,382.62 for 60 days at 9%
$20.60 = $1,382.62 x ((1 +.09/365)60 -1)

To calculate interest on $1,382.62 for 60 days at 9% and then 90 days at 11%, follow Steps 1 through 5, then:

Total interest due is $59.17 ($20.60 + $38.57)

Please note that the $20.60 interest calculated at 9% is added to the $1,382.62 assessment amount before multiplying by the 11% factor for the subsequent interest period.  The calculated interest for each period must be added to the assessment amount and becomes the new assessment amount for each additional interest period.