This document contains final regulations relating to the notice to interested parties requirement. Before the IRS can issue an advance determination regarding the qualification of a retirement plan, a plan sponsor must provide evidence that it has notified all persons who qualify as interested parties that an application for an advance determination will be filed with the IRS. These regulations set forth standards by which a plan sponsor may satisfy the notice to interested parties requirement. The final regulations affect retirement plan sponsors, plan participants and other interested parties with respect to a determination letter application, and certain representatives of interested parties.