This document is a sole source determination for FirstNet to procure memberships and related fees from the Alliance for Telecommunications Industry Solutions (ATIS). This acquisition is deemed essential for FirstNet to fulfill its statutory mission under the Middle Class Tax Relief and Job Creation Act of 2012. The Act mandates FirstNet to build and operate a wireless broadband network for first responders using open standards and LTE technology, while also representing public safety interests in relevant standards organizations. ATIS and 3GPP are identified as the only standards bodies that can provide the necessary participation for FirstNet to develop critical public safety features and capabilities for the National Public Safety Broadband Network (NPSBN). Specifically, 3GPP is the sole organization responsible for creating and evolving the mandated technology and defining mission-critical services. ATIS is the only North American organization providing industry oversight and is the exclusive means for a US entity to obtain 3GPP membership. Additionally, ATIS uniquely manages the essential Public Land Mobile Network (PLMN) IDs required for FirstNet network operation. The contracting officer has determined that ATIS is the only source capable of meeting these unique requirements.