Mo. Rev. Stat. § 138.140: Board of equalization — members — oath — compensation — vacancies, how filled.

1. In all constitutional charter cities not situated within any county there shall be a board of equalization consisting of the assessor, who shall be its president, and four taxpaying, property-owning citizens resident in the city for five years next before their appointment, who shall be appointed annually by the mayor on or before the second Monday in May of each year.

2. Each member shall take an oath similar to that required by law of members of county boards of equalization.

3. Their compensation shall be fixed by ordinance.

4. Vacancies or absences on the board of equalization caused by death, incapacity to perform duties, failure to attend three consecutive meetings, or resignation shall be filled forthwith by appointment by the mayor.