Mo. Rev. Stat. § 86.187
Regular interest charges payable, the creation and maintenance of reserves in the pension accumulation fund and the maintenance of annuity reserves and pension reserves as provided for and the payment of all pensions, annuities, retirement allowances, refunds and other benefits granted under the provisions of sections 86.010 to 86.193 and all expenses in connection with the administration and operation of the retirement system are hereby made obligations of the said cities. All income, interest and dividends derived from deposits and investments authorized by sections 86.010 to 86.193 shall be used for the payment of the said obligations of the said cities. Any amounts derived therefrom, which, when combined with regular appropriations made under the provisions of sections 86.010 to 86.193, exceed the amount required to provide such obligations, shall be used to reduce the regular appropriations otherwise required.
§ 86.187, RSMo