All U.S. companies are required to have an Employer Identification Number or EIN. The IRS uses this number, which consists of nine digits, to identify businesses for tax purposes. Think of it as a Social Security number for a company, corporation or any other legal entity that has employees, incorporates an LLC or forms a partnership.

Tax ID Lookup 

Individuals and businesses can look up the EIN by company name, address and other relevant information. They may also use an EIN lookup database to find out more about a company's ownership, structure and revenue. If you need to find the name of a large or publicly-held company knowing only the EIN, there are online services that can help.

Before getting started, gather information about the company you're searching for. The more you know about it, the better. In addition to its EIN, try to find out what its legal business structure is or where it operates. This will give you a better picture of what to look for and help with your EIN number lookup.

The IRS does not provide information about a company based on its EIN. The only exceptions are charities and tax-exempt organizations. If you need to find a charity’s name, access the IRS website.

Go to Charities and Non-Profits, click Search for Charities and then select Tax Exempt Organization Search. On this page, you can run an EIN number search. Simply enter the tax ID number in the designated field along with any other information you may have, such as the company's location.

Check Online Databases

If the company you're researching is not a charity, use EIN lookup databases to find its name. Try EIN Finder, Real Search, FEIN Search, SEC Info and other similar services. Most platforms retrieve this information from the US SEC EDGAR database, a leading provider of company data derived from filings and other official documents.

Some of these services are free to use, while others require a subscription. FEIN Search, for example, provides five free instant searches. EIN Finder offers monthly and yearly subscription plans.

Another option is to check the EIN lookup database provided by your local Department of State. For instance, Pennsylvania's Department of State website allows users to search for business entities based on their names or tax IDs.

Most organizations choose to keep their EIN number private. However, this unique identifier can be usually found online for publicly traded companies. In this case, you can use Google or other search engines to do an EIN number lookup and retrieve the information you need.

Hire a Private Investigator

If everything else fails, consider hiring a private investigator. They have the tools and resources needed to find a company's name and other business data based solely on its EIN.

Beware that sole proprietors are not required to have an EIN number unless they hire employees, file for bankruptcy or form a partnership. If you cannot find a company's name based on its EIN, it could be due to the fact that it's a sole proprietorship.