The paper examines the development of Cassa Depositi and Prestiti (CDP), which originated in the Kingdom of Sardinia (1850) as a fundraising institution for public interests, extended to all of Italy (1863), as a branch of the Ministry of Treasury. Over time, the main funding source changed to postal savings. After World War I, CDP was an active part of thew new political climate of public intervention: it helped also to found IMI (1931) and IRI (1933). After World War II, CDP invested in reconstruction. Afterwards, for a long period of time, CDP mainly financed government public spending, buying state-bonds and giving loans to local public administrations. In 2003 the Minister of Economy, Giulio Tremonti, transformed CDP into a company, with 65 banking foundations as minority stockholders. So, CDP leaves the perimeter of public budgeting and joins the traditional public economy sector, also the business development sector, financing export, internationalization, and assumes minority and majority participation in public utility companies and in other business. From 2001 CDP may finance entirely private business through the subsidiary “Fondo Strategico Italiano (FSI)” (today CDP Equity). In 2015, the Juncker Plan recognizes CDP with the status of “National Promotion Institute”. The paper explores the new governance of CDP from a public choice industrial economic perspective, with an analysis of yearly reports of CDP, in the context of new Italian public interventionism. In fact, the institute has a huge development opportunity, especially in “strategic” sectors of the Italian economy. On the other hand, the risk is that heterogeneous interventions, inspired by the opportunistic behavior of politicians and other private shareholders (banking foundations), without a coherent industrial policy strategy, could not only distort the functioning of market economy but also deteriorate the equity of CDP with negative effects on the main funding source (postal savings).