An architecture firm in the United States usually has at least one "principal," a licensed architect who is the sole proprietor of the firm, or one who shares an ownership interest with the other architects in the firm (either as a partner in a partnership, or as a shareholder in a corporation).[5] Sometimes the title of principal is limited to owners who hold a certain percentage of ownership interest in a firm, or it may be expanded to include anyone with a leadership role in a firm.[5] Some firms may also use the title "principal-in-charge," which denotes an architect who oversees the firm's services in connection with a specific project.[5]