What is Employer Identification Number (EIN) Certificate?

An Employer Identification Number (EIN) Certificate is a document issued by the Internal Revenue Service (IRS) in the United States that confirms a business’s unique EIN, which is used for tax administration purposes. For a UK audience, understanding the EIN Certificate can be helpful, especially for businesses engaging in international trade or operating subsidiaries in the US.


Key Aspects of an EIN Certificate:

  1. Definition:
    • An Employer Identification Number (EIN) is a unique nine-digit number assigned by the IRS to identify a business entity for tax purposes. The EIN Certificate is the official document provided by the IRS confirming this number.
  2. Purpose:
    • Tax Identification: The EIN is used to identify a business for federal tax purposes, similar to the way National Insurance numbers are used for individuals in the UK.
    • Business Transactions: An EIN is required for various business activities, including opening a bank account, applying for business licenses, and filing tax returns.
    • Employee Management: Businesses use their EIN when reporting employment taxes and other employee-related tax information to the IRS.
  3. Application Process:
    • Who Needs an EIN: Any business operating in the US, including sole proprietorships, partnerships, corporations, and non-profit organizations, typically needs an EIN.
    • How to Apply: Businesses can apply for an EIN online, by fax, or by mail using IRS Form SS-4. The process involves providing information about the business, such as its legal name, mailing address, and the responsible party’s details.
    • Issuance: Once the application is processed, the IRS issues the EIN Certificate, which can be received immediately online or by mail.
  4. Uses of the EIN Certificate:
    • Tax Filings: The EIN is used to file federal tax returns, including income, employment, and excise taxes.
    • Banking: Opening business bank accounts and applying for business loans typically require an EIN.
    • Legal Compliance: The EIN is necessary for compliance with federal regulations, such as obtaining business licenses and permits.
    • Employee Reporting: Businesses use their EIN to report employee wages and taxes to the IRS.
  5. Example for a UK Business:A UK-based company plans to establish a subsidiary in the United States. The subsidiary will need to apply for an EIN to comply with US tax regulations and conduct business activities.
    • Application: The UK company completes IRS Form SS-4, providing details about the new US subsidiary.
    • Issuance: The IRS processes the application and issues an EIN Certificate, which includes the unique nine-digit EIN.
    • Usage: The US subsidiary uses the EIN to open a bank account, file tax returns, and report employee taxes.


An Employer Identification Number (EIN) Certificate is a crucial document for businesses operating in the United States. For UK businesses with US subsidiaries or those planning to expand to the US, understanding the purpose and application process of the EIN is essential for compliance with US tax laws and smooth business operations. The EIN serves as the primary tax identification number for businesses, facilitating various legal and financial activities in the US.