The presence of illegal organizations in economic development settings contributes to the Italian economy’s regional heterogeneity by exacerbating other inefficiencies. We aim to investigate how three indicators of awareness of criminal interest in a firm’s activities affect the latter’s efficiency, as well as examining a potential channel through which illegal activities could hinder firm performance, using a unique set of firm-level data. According to our findings, the presence of criminal network pressure in a firm’s environment reduces its technical efficiency and propensity to invest. This phenomenon is particularly strong in Italy’s underdeveloped regions, across all illicit considered and risk classes, with inefficiency doubling when the fear of crime becomes significant. A similar pattern emerges in terms of firm investment proclivity. The research findings are relevant for policymakers because they demonstrate that even the perception of a criminal threat has significant effects on a firm’s performance; consequently, enhancing legal protection could prevent significant economic and social costs.