This document contains final regulations relating to the abatement of interest attributable to unreasonable errors or delays by an officer or employee of the IRS in performing a ministerial or managerial act. The final regulations reflect changes to the law made by the Tax Reform Act of 1986 and the Taxpayer Bill of Rights 2. The final regulations affect both taxpayers requesting abatement of certain interest and IRS personnel responsible for administering the abatement provisions.