26 U.S.C. § 8021

(a) To obtain data and inspect income returns For powers of the Joint Committee to obtain and inspect income returns, see section 6103(f). (b) Relating to hearings and sessions The Joint Committee, or any subcommittee thereof, is authorized— (1) To hold To hold hearings and to sit and act at such places and times; (2) To require attendance of witnesses and production of books To require by subpoena (to be issued under the signature of the chairman or vice chairman) or otherwise the attendance of such witnesses and the production of such books, papers, and documents; (3) To administer oaths To administer such oaths; and (4) To take testimony To take such testimony; as it deems advisable. (c) To procure printing and binding The Joint Committee, or any subcommittee thereof, is authorized to have such printing and binding done as it deems advisable. (d) To make expenditures The Joint Committee, or any subcommittee thereof, is authorized to make such expenditures as it deems advisable. (e) Investigations The Joint Committee shall review all requests (other than requests by the chairman or ranking member of a committee or subcommittee) for investigations of the Internal Revenue Service by the Government Accountability Office, and approve such requests when appropriate, with a view towards eliminating overlapping investigations, ensuring that the Government Accountability Office has the capacity to handle the investigation, and ensuring that investigations focus on areas of primary importance to tax administration.