["Oxford Bulletin of Economics and Statistics, Volume 88, Issue 3, Page 426-440, June 2026. ", "\nABSTRACT\nThis paper investigates the effectiveness of private actors in contributing to crime prevention. We leverage well‐publicised increases in security measures, including additional security guards and tagging of goods, by Tesco, a large UK supermarket chain. Utilising geocoded administrative crime data and address information of supermarkets in Greater London, we compare streets near a Tesco supermarket with two control areas in a differences‐in‐differences design. Results suggest that Tesco's security enhancements led to a significant decrease in shoplifting. We also investigate crime displacement to other major supermarkets and other shops.\n"]