Who is the responsible party on the EIN SS-4 application?

Form SS-4 is the Application for Employer Identification Number (EIN). The IRS requires a “responsible party” to be named on the EIN application.

The “responsible party” on the SS-4 application is the individual who has ultimate control over the entity.

This person must be a natural person—not another business or entity—and is typically:

• For Sole Proprietorships: The sole owner.
• For Partnerships: A general partner or someone with significant control.
• For Corporations: A principal officer (such as the president, CEO, or another executive with significant decision-making authority).
• For LLCs: The managing member or a person with control over the company.
• For Trusts: The grantor or trustee, depending on the trust type.

In all cases, the responsible party is the person who ultimately owns or controls the entity and must have a valid Social Security number (or ITIN, as applicable).