Mo. Rev. Stat. § 148.370
Every insurance company or association organized under the laws of the state of Missouri and doing business under the provisions of sections 376.010 to 376.670, 379.205 to 379.310*, 379.650 to 379.790 and chapter 381 and every mutual fire insurance company organized under the provisions of sections 379.010 to 379.190 shall, as hereinafter provided, quarterly pay, beginning with the year 1983, a tax upon the direct premiums received by it from policyholders in this state, whether in cash or in notes, or on account of business done in this state, in lieu of the taxes imposed under the provisions of chapters 143 and 147 for insurance of life, property or interest in this state, at the rate of two percent per annum, which amount of taxes shall be assessed and collected as hereinafter provided; provided, that fire and casualty insurance companies or associations shall be credited with cancelled or returned premiums actually paid during the year in this state, and that life insurance companies shall be credited with dividends actually declared to policyholders in this state but held by the company and applied to the reduction of premiums payable by the policyholder.
§ 148.370, RSMo