Mo. Rev. Stat. § 383.037: Rates, requirements.

The rates made by each association licensed pursuant to sections 383.010 to 383.040 shall be subject to the following provisions:

(1) Rates shall not be excessive or inadequate, nor shall they be unfairly discriminatory;

(2) No rate shall be held to be excessive unless such rate is unreasonably high for the insurance provided with respect to the classification to which such rate is applicable;

(3) No rate shall be held to be inadequate unless such rate is unreasonably low for the insurance provided with respect to the classification to which such rate is applicable.