Maryland Code, Corporations and Associations § 5-104

(a) A professional corporation may not render a professional service or engage in an activity other than the professional service authorized by its articles of incorporation.

(b) Except as provided in subsection (c) of this section, subsection (a) of this section does not prohibit a professional corporation from investing its funds in real estate, mortgages, securities, or any other type of investment.

(c) A professional corporation may not, through any investment, subsidiary, or other means, engage or participate in the active management of any entity, association, or venture whose business purpose is not reasonably related to the rendering of a professional service authorized by its articles of incorporation.