professional service employer
(2) For purposes of this paragraph and for purposes of subsection (b)(13)— (A) the term “professional service employer” means any proprietorship, partnership, corporation, or other association or organization (i) owned or controlled by professional individuals or by executors or administrators of professional individuals, (ii) the principal business of which is the performance of professional services, and (B) the term “professional individuals” includes but is not limited to, physicians, dentists, chiropractors, osteopaths, optometrists, other licensed practitioners of the healing arts, attorneys at law, public accountants, public engineers, architects, draftsmen, actuaries, psychologists, social or physical scientists, and performing artists.