Miss. Code Ann. § 29-1-141

All due but unpaid and delinquent sums shall bear interest at the rate of one half of one percent (1/2 of 1%) a month from the month in which due until paid, and a fractional month shall be considered a month. Any amount not reported and paid when due shall be increased by a penalty of ten percent (10%) and interest on the principal, as in other cases of nonpayment.