26 U.S.C. § 7121 - U.S. Code - Unannotated Title 26. Internal Revenue Code § 7121. Closing agreements

(a) Authorization.--The Secretary is authorized to enter into an agreement in writing with any person relating to the liability of such person (or of the person or estate for whom he acts) in respect of any internal revenue tax for any taxable period.

(b) Finality.--If such agreement is approved by the Secretary (within such time as may be stated in such agreement, or later agreed to) such agreement shall be final and conclusive, and, except upon a showing of fraud or malfeasance, or misrepresentation of a material fact--