The IRS is headed by the Commissioner of Internal Revenue, an appointed position requiring Senate confirmation. The Commissioner is one of only two positions within the agency requiring Senate confirmation; the other position is that of the Chief Counsel. In 1998, Congress established a five-year term for the position of Commissioner, in part to provide continuity and help insulate tax administration from political pressure. Prior to 1998, the average term of a Commissioner had been three years.
Reporting directly to the Commissioner are two Deputy Commissioners, the highest ranking career employees within the agency. The Deputy Commissioner for Services and Enforcement oversees the four primary operating divisions and other service and enforcement functions. The Deputy Commissioner for Operations Support oversees the support functions including information technology, human resources, agency finances and privacy. Other direct reports to the Commissioner include the IRS Chief Counsel, the Director of IRS Appeals, the Taxpayer Advocate as well as offices responsible for diversity, statistical research and media relations.
From the standpoint of tax law enforcement, the Deputy Commissioner for Services and Enforcement is the relevant official. The four operating divisions reporting to that office are the Wage and Investment Division, the Large Business and International Division, the Small Business/Self-Employed Division and the Tax-Exempt and Government Entities Division. Additional functions reporting to the Deputy Commissioner include Criminal Investigation, the Office of Professional Responsibility and the Whistleblower Office.
As is reflected in their names, the operating divisions are organized around particular categories of taxpayers, rather than types of tax or functions, and, as a general jurisdictional principle, the operating divisions will not interact with taxpayers that are the responsibility of a different division without coordination or prior clearance. Certain exceptions do exist, however, for example, the excess benefits excise tax in section 4958 is payable by the individual who receives the excess benefit, not the charity that provides it. That particular Code section is administered by the Tax-Exempt and Government Entities Division, rather than the Wage and Investment Division.