Me. Rev. Stat. tit. 32, § 13181

The director shall issue to each agency a license in the form and size prescribed by the Commissioner of Professional and Financial Regulation. The license of each broker, associate broker and sales agent must be delivered or mailed to the designated broker and be kept in the custody and control of the designated broker. It is the duty of the designated broker to conspicuously display the agency license in the broker's place of business.