The IRS uses eins to identify entities that are required to file various tax forms. Essentially, it is equivalent to a social security number for a business.
EIN information is sourced through public filings through the Department of Labor and the Internal Revenue Service, both current and historical. Data Axle has compiled historical data since 1994.
Banks and insurance companies have expressed strong interest in this data for the verification and authentication of a business. It also aids in looking up companies through government agencies.
See Also:
eins_count- Data Dictionary