Mississippi Code Title 27. Taxation and Finance § 27-67-19

The commissioner may grant a reasonable extension of time for making any return and paying the tax due thereon, but the time for filing any such return shall not be extended beyond the twentieth of the month next succeeding the regular due date of such return without the imposition of interest at the rate of one-half of one percent ( 1/2 of 1%) per month, or fractional part of a month, from the regular due date of such return until the tax is paid.

For persistent, willful or recurring failure to make any return and pay the tax shown thereby to be due, by the time specified herein, there shall be added to the amount of tax shown to be due, ten percent (10%) damages, or interest at the rate of one-half of one percent ( 1/2 of 1%) per month, or both.