Check the business’s tax documents, such as IRS letters, prior tax returns, or payroll forms
Look for the EIN on Form W-2, Form 1099, Form 941, or other IRS filings
Ask the business owner, accountant, or payroll provider
Search state business registration records if the EIN is listed there
Review bank account opening documents or loan paperwork for the business
Contact the IRS Business & Specialty Tax Line at 800-829-4933 if you are authorized to obtain it
Use the IRS EIN verification process if you are a third party with proper authorization
Check business credit reports or vendor records if you have access to them