This research responses to §875 of the 2016 National Defense Authorization Act, directing the Department of Defense (DOD) to conduct a review of (1) regulations and practices relating to access to intellectual property (IP) data and rights in acquiring weapon systems; and (2) IP-related practices to facilitate ompetition in sustainment of weapon systems. IDA reviewed regulations and guidance documents to identify provisions regarding IP data and rights to enable sustainment. IDA sent questionnaires to major DOD depots requesting them to identify impacts of failure to acquire IP data. To evaluate practices regarding IP in sustainment, IDA visited several DOD acquisition and logistics offices. The research identified the difficulties DOD faces in acquiring IP data and rights and the implications of failure to obtain IP data. IDA identified the major cause of the inability to acquire IP data and rights to be the sole-source relationships that DOD enters into for the acquisition and sustainment of most major systems. The research suggests the need for better oversight of processes for acquiring IP data and rights; increased use of commercial approaches to maintenance of DOD aircraft; and increasing the availability of legal and technical experts in IP to acquisition management organizations.