Find the Employer Identification Number, or EIN, for a business by looking at the original notice from the Internal Revenue Service when the EIN was issued or by referencing a previous year's business tax return. If the business opened a bank account, the bank can provide the EIN.
If the business has any licenses or permits, the issuing agency can also provide the business EIN.
Business owners unable to locate their EINs can call the IRS Business & Specialty Tax Line at 800-829-4933. Agents are available Monday through Friday between 7:00 a.m. and 7:00 p.m. in the local time zone. An EIN can be released only to authorized individuals, such as business owners or partners, corporate officers and trustees of a related trust.
If a person runs a business as a sole proprietor, he might not need an EIN unless he has employees or has a Keogh or Solo 401(k) retirement plan. A sole proprietorship that does not meet these conditions may file taxes under the owner's Social Security number.
If the business structure changes, the IRS requires the owner to obtain a new EIN. This might happen if the business structure changes between a sole proprietorship, partnership, LLC or corporation, or if the business files for bankruptcy.