The paper analyses, for the period 1998-2002, the effects of the reform of local public
transit in Piedmont on the structure and efficiency of the regional bus transport industry. A data base covering almost all the firms concerned allows to distinguish the performances of private and public-owned firms. The industry became more concentrated after the merger (2002) between the two large public-owned firms operating in the metropolitan area and the widespread diffusion of informal groups of economic operators not assuming a specific legal form, ATI in Italian. Technical and economic efficiency
indicators, as well as a DEA application, show on average a slight improvement at the end of the period, with poorer performances for the public owned companies.