Mo. Rev. Stat. § 404.530

An adult person or financial institution shall not be qualified to be designated personal custodian for property of a beneficiary 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 beneficiary 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 personal custodian for the beneficiary under sections 404.400 to 404.650 subjects the person to removal as personal custodian under subsection 9 of section 404.590, but does not affect the beneficiary's ownership of the property and the immunities of third persons dealing with the personal custodian, nor relieve the unqualified person of any duties or responsibilities imposed on personal custodians under sections 404.400 to 404.650.