An Employer Identification Number (EIN) is a unique nine-digit number assigned by the Internal Revenue Service (IRS) to businesses operating in the United States. It serves as the business’s tax ID and is used for hiring employees, opening bank accounts, and submitting tax filings. It is also required when applying for a merchant account or payment gateway. The EIN is used by payment providers to verify business legitimacy and ensure compliance.

When opening a U.S. merchant account through AltoPay, your EIN is required to validate your entity and meet IRS and anti money laundering (AML) requirements. Submitting accurate EIN documentation helps streamline underwriting and ensures tax reporting is filed correctly. If your business structure changes, it’s important to update your EIN to avoid delays or rejections. Keeping this information aligned with your bank and corporate records avoids conflicts later on.