Maryland Code, Corporations and Associations § 5-102

(a)(1) Except as permitted under subsection (b) of this section, a corporation may be a professional corporation under § 5-112 of this subtitle solely for the purpose of rendering professional services within a single profession.

(2) Except as provided in paragraph (3) of this subsection, a corporation that is eligible to be a professional corporation under this subtitle may not organize under any other corporate form permitted by this article.

(3) Paragraph (2) of this subsection does not apply to professional services rendered by: