Mo. Rev. Stat. § 86.350: City obligated to pay cost of benefits and one-half of expenses.

The payment of the cost of providing all benefits granted under the provisions of sections 86.200 to 86.366, as determined pursuant to section 86.337, and the payment of fifty percent of all expenses described in subsection 2 of section 86.343 incurred in connection with the administration and operation of the retirement system are hereby made obligations of the cities.