American Bar Association Model Rules of Professional Conduct - Rule 5.4. Professional Independence of a Lawyer
(a) A lawyer or law firm shall not share legal fees with a nonlawyer, except that:
(1) an agreement by a lawyer with the lawyer's firm, partner, or associate may provide for the payment of money, over a reasonable period of time after the lawyer's death, to the lawyer's estate or to one or more specified persons;
(2) a lawyer who purchases the practice of a deceased, disabled, or disappeared lawyer may, pursuant to the provisions of Rule 1.17, pay to the estate or other representative of that lawyer the agreed-upon purchase price;
(3) a lawyer or law firm may include nonlawyer employees in a compensation or retirement plan, even though the plan is based in whole or in part on a profit-sharing arrangement; and
(4) a lawyer may share court-awarded legal fees with a nonprofit organization that employed, retained or recommended employment of the lawyer in the matter.
(b) A lawyer shall not form a partnership with a nonlawyer if any of the activities of the partnership consist of the practice of law.
(c) A lawyer shall not permit a person who recommends, employs, or pays the lawyer to render legal services for another to direct or regulate the lawyer's professional judgment in rendering such legal services.
(d) A lawyer shall not practice with or in the form of a professional corporation or association authorized to practice law for a profit, if:
(1) a nonlawyer owns any interest therein, except that a fiduciary representative of the estate of a lawyer may hold the stock or interest of the lawyer for a reasonable time during administration;
(2) a nonlawyer is a corporate director or officer thereof or occupies the position of similar responsibility in any form of association other than a corporation ; or
(3) a nonlawyer has the right to direct or control the professional judgment of a lawyer.