and addresses of contributors (a) In general Section 6033(a)(1) of the Internal Revenue Code of 1986 is amended by adding at the end the following: Except as provided in subsections (b)(5) and (g)(2)(B), such annual return shall not be required to include the names and addresses of contributors to the organization. . (b) Application to section 527 organizations Section 6033(g)(2) of such Code is amended— (1) by striking and at the end of subparagraph (A), (2) by redesignating subparagraph (B) as subparagraph (C), and (3) by inserting after subparagraph (A) the following new subparagraph: (B) containing the names and addresses of all substantial contributors, and . (c) Effective date The amendments made by this section shall apply to taxable years ending after the date of the enactment of this Act.