The Sicilian economy has four characteristics that make it vulnerable to penetration by criminal organizations. First, it has a relatively high proportion of traditional sectors, such as the construction sector, whose activities are located in defined territories. Second, these sectors are skewed toward small firms. Third, the economic sectors operate at a relatively low technological level. Fourth, the public sector of the economy in Sicily is significantly larger than Italy’s national average. These features of the Sicilian economy make it fertile soil for the propagation of typical activities of criminal organizations against businesses, such as extortion of businesses and cartel enforcement of its demands on businesses in a given territory. This study argues that the probability of a firm becoming a target of extortion by organized crime is higher when the firm has difficulty obtaining protection from other organizations or institutions, i.e., in areas where legal institutions are weak or corrupt. Also, when the size of outputs and profits is easily observed for small firms, organized criminal groups can identify targets that can pay protection money. Further, the smaller the firm and thus the lower the number of employees, the lower the probability that the extortion will be revealed outside the firm. In addition, there is usually just one owner that the criminals can deal with directly. Another factor concerns the concentration of a firm‘s activities in a given territory, which facilitates the provision of protection and the enforcement of the extortion. 3 figures, 14 tables and 68 notes