Internal Revenue Service (IRS)
The Internal Revenue Service is the revenue service of the United States federal government. The agency is a bureau of the Department of the Treasury, and is under the immediate direction of the Commissioner of Internal Revenue. The IRS is responsible for collecting taxes and the interpretation and enforcement of the Internal Revenue Code. The IRS is responsible for the interpretation and enforcement of all tax-deferred savings plans, which include employer-sponsored defined contribution plans that include 401(k) plans, 403(b) plans and 457 plans as well as tuition assistance programs such as 529 plans.