Mo. Rev. Stat. § 339.020: Brokers and salespersons, unlawful to act without license.

It shall be unlawful for any person, partnership, limited partnership, limited liability company, association, professional corporation, or corporation, foreign or domestic, to act as a real estate broker, real estate broker-salesperson, or real estate salesperson, or to advertise or assume to act as such without a license first procured from the commission.