A federal employer identification number (FEIN), or, less commonly, a federal tax identification number (FTIN), is a unique number assigned by the Internal Revenue Service (IRS) to businesses operating in the United States for the purposes of identification. Every employer who pays wages is required to have an FEIN.
An FEIN is a crucial identifier for businesses, as it enables them to file taxes, open bank accounts, and hire employees. Historically, the FEIN was referred to as the Employer Identification Number (EIN) until the late 1990s, when the IRS expanded its use to non-employer entities such as trusts, estates, and partnerships, leading to its official name change to the more inclusive FEIN.