Defense Acquisition Trends 2021 is the latest in an annual series of CSIS reports examining trends in what the DoD is buying, how the DoD is buying it, and from whom the DoD is buying using data from the Federal Procurement Data System (FPDS). This report analyzes the current state of affairs in defense acquisition by combining detailed policy and data analysis to provide a comprehensive overview of the current and future outlook for defense acquisition. It provides critical insights into understanding the current trends in the defense-industrial base and the implications of those trends on acquisition policy.