This document contains final regulations relating to changes made to Internal Revenue Code sections 2001, 2504, and 6501 by the Taxpayer Relief Act of 1997 and the Internal Revenue Service Restructuring and Reform Act of 1998 regarding the valuation of prior gifts in determining estate and gift tax liability, and the period of limitations for assessing and collecting gift tax. These regulations are necessary because section 6501(c)(9) now requires that a gift must be adequately disclosed on a gift tax return in order to commence the running of the period of limitations on assessment with respect to the gift. Once the period of limitations expires, the amount of that gift as reported on the return may not be adjusted for purposes of determining future gift and estate tax liability. The regulations provide guidance on what constitutes adequate disclosure for purposes of the statute.