Check the IRS EIN confirmation letter
Call the IRS Business and Specialty Tax Line at 800-829-4933
Compare the EIN with official business tax documents
Verify the EIN on filed tax returns and payroll records
Ask the business to provide a completed Form W-9
Confirm the EIN through state business registration records if available
Use the SEC EDGAR database for publicly traded companies
Match the EIN with bank, vendor, or payroll account records
Contact the business directly using verified contact information
Request a signed letter from the business confirming the EIN