; (2) in section 9, by inserting after the fourth undesignated paragraph the following: Upon the application of the commission with respect to any activity related to the consummation of a proposed merger, acquisition, joint venture, or similar transaction that is subject to section 7 of the Clayton Act ( 15 U.S.C. 18 ) that may result in any unfair method of competition, the district courts of the United States shall have jurisdiction to issue writs of mandamus commanding any person or corporation to comply with the provisions of this Act or any order of the commission made in pursuance thereof. ; (3) in section 13(b)(1), by inserting (excluding section 7 of the Clayton Act ( 15 U.S.C. 18 ) and section 5(a)(1) with respect to the consummation of a proposed merger, acquisition, joint venture, or similar transaction that is subject to section 7 of the Clayton Act ( 15 U.S.C. 18 )) after Commission ; and (4) in section 20(c)(1), by inserting or under section 7 of the Clayton Act ( 15 U.S.C. 18 ), where applicable, after Act, . 4. Effective date; application of amendments (a) Effective date Except as provided in subsection (b), this Act and the amendments made by this Act shall take effect on the date of the enactment of this Act. (b) Application of amendments The amendments made by this Act shall not apply to any of the following that occurs before the date of enactment of this Act: (1) A violation of section 7 of the Clayton Act ( 15 U.S.C. 18 ). (2) A transaction with respect to which there is compliance with section 7A of the Clayton Act ( 15 U.S.C. 18a ). (3) A case in which a preliminary injunction has been filed in a district court of the United States.