Mo. Rev. Stat. § 404.035
An adult person or financial institution shall not be qualified to be designated custodian for property of a minor who is a resident of this state if the person or financial institution is not qualified to be appointed conservator of the estate of the minor under subsection 2 of section 475.055 or if the financial institution is not legally authorized to do business in this state. A transfer of property to a person not qualified to act as custodian for the minor under sections 404.005 to 404.094 subjects the person to removal as custodian under subsection 11 of section 404.057, but does not affect the minor's ownership of the property and the immunities of third persons dealing with the custodian, nor relieve the unqualified person of any duties or responsibilities imposed on custodians under sections 404.005 to 404.094.
§ 404.035, RSMo