For purposes of the preceding paragraph, a U.S. entity is a firm incorporated in the United States (or an unincorporated U.S. firm with its principal place of business in the United States) that is controlled by U.S. citizens or by another U.S. entity. An entity is not a U.S. entity if 50 percent plus one share of its stock (if a corporation, or a similar ownership interest of an unincorporated entity) is controlled, directly or indirectly, by non-U.S. citizens or non-U.S. entities.