An online Federal Employer Identification Number search service, such as KnowX, can be used to verify the Employer Identification Number of a company. KnowX is a free service, while many FEIN search services are fee-based.
FEIN search services may not be complete. In particular, recently issued EINs may not show up in search results. Tax advisers may be able to verify an IRS EIN when an online search fails.
The Exempt Organization Select Check is a free search service provided by the Internal Revenue Service. It can be used to verify the IRS EIN of organizations that are eligible to receive tax-deductible donations. It can also be used to verify the tax-exempt status of an organization.