Small business owners often name themselves the responsible part when applying for an EIN. The responsible party is a person who has control over, or is entitled to the funds or assets of the business. In a single-owner business, the owner is that person. The responsible party also controls, manages, and directs the sale, transfer, or assignment of these funds. Again, that's the business owner in a single-owner business. If your small business is a partnership or LLC with multiple members, the managing partner or limited liability company (LLC) member-manager may be the responsible party. An LLC may also have a manager to manage day-to-day operations. This person would be the responsible party.