Mo. Rev. Stat. § 86.359
Current with changes from the 2023 Legislative Session
If a retroactive payment is made to a member, surviving spouse, dependent child, or other beneficiary under sections 86.200 to 86.366 for any reason, a lump sum equal to the sum of the retroactive monthly payments, plus interest, shall be paid. For this purpose, interest shall be credited at the rate of six percent annum, compounded annually.
§ 86.359, RSMo