This report presents learning gathered during an incubator project supported by the What Works Collaborative to investigate the availability of investment data in several cities. We find that the extent and quality of local data needed for tracking investment flows has improved dramatically in many places. While exhaustive quantification is probably not possible anywhere, a fairly complete picture is now available in some cities. Given the considerable interest in this topic from policy and practitioner audiences, we feel this argues for initiating a research study to quantify investment flows in a small number of targeted cities and neighborhoods.