Defense Acquisition Trends 2021 is the latest in an annual series of CSIS reports examining trends in what the Do D is buying, how the Do D is buying it, and from whom the Do D 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.