A bill to insure the confidentiality of information filed by individual taxpayers with the Internal Revenue Service pursuant to the Internal Revenue Code and, at the same time, to insure the effective enforcement of Federal and State criminal laws and the effective administration of justice.

[AI summary unavailable — showing source text] Amends the Internal Revenue Code to revise the definition of "return information." Defines as "nonreturn information" identifying information: (1) collected by the Secretary of the Treasury with respect to a taxpayer or return relating to liability for any penalty; and (2) any part of any written determination or any background file document closed to public inspection. Allows disclosure of return information to an officer or employee of the Department of Justice for use in preparing any administrative, judicial, or grand jury proceedings involving the enforcement of a specific Federal criminal statute (but not involving tax administration) or in an investigation which may result in such a proceeding. Authorizes such disclosure only by ex parte order of a Federal district court judge or magistrate. Sets forth grounds for the granting of such order. Permits further disclosure by the Government attorney who has authorized the application for the ex parte order to Government personnel required to assist in a criminal investigation. Requires the Secretary to disclose nonreturn information (other than nonreturn information which would identify a confidential informant or seriously impai…