This article aims to show the role of Banco di Napoli in the 1950s. How did this bank chose the right clients? Who deserved its trust? I analyse the cases in which the risk connected with credit intermediation was sustainable for the bank, and how the bank defended its choices and the facilities accorded to clients. Doing so makes it possible to read differently the modernity of the bank in the contemporary age. The historiographical discourse on credit has often seen the twentieth century as an important divide: according to this point of view the success of the bank system caused the decline of the informal logic which was typical of the modern age in order to improve formalised and impersonal credit practices. Contemporary dynamics of credit are much less linear. Through the analysis of specific case studies it will be possible to show that the opposition between formal and informal credit looses its efficacy when we consider the effective choices of a bank. Documents show that Banco di Napoli was not only attentive to real warranties offered by clients, but it also gave great importance to the morality, the behaviour and the social and professional status of its clients. These are important elements for understanding the role of banks in the contemporary credit market.