To address the a lack of information on the role of private investors in acquiring foreclosed properties in low-income communities in the wake of the housing bust, the What Works Collaborative funded a series of case studies in four market areas representing a range of market conditions: Atlanta, Boston, Cleveland, and Las Vegas. This report synthesizes the findings from the four case studies to identify common themes that emerged about the nature of investor activity, the potential impact of their activities on neighborhood conditions, and implications of these findings for public policy and ongoing research.