Mo. Rev. Stat. § 443.453

Financial institutions, as defined in section 381.410, which are mortgage servicers, shall pay property tax obligations which they service from escrow accounts, as defined in Title 24, Part 3500, Section 17, Code of Federal Regulations, in one annual payment before the first day of January of the year following the year for which the tax is levied. Escrow accounts established between such financial institutions and borrowers are contractually binding and may disallow the payment of property taxes more than once a year as such payments are authorized in section 139.053.