Founded in 1862, the U.S. Internal Revenue Service (IRS) is a bureau of the U.S. Department of Treasury. The bureau is one of the most efficient tax administrators in the world. It helps the citizens of the United States to understand and meet their tax responsibilities by applying the tax law with integrity and fairness to all. The bureau functions under four major operating divisions; large and mid-size business (LMSB), small business or self-employed (SB/SE), wage and investment (W&I) and tax exempt and government entities (TE/GE). The U.S. Internal Revenue Service also operates a criminal law enforcement division, called the IRS Criminal Investigation Division.