From the last decades of the twentieth century, above all, in the more service-oriented post-industrial economies, and in a context of debilitation of public health systems, health care became exponentially profitable, thereby attracting new types of investors. In fact, this new stage entails moving from the commercialisation of health care to its financialisation; that is, medical care becomes just one more financial asset and its price and quality are quoted on the stock exchange. This study intends to participate in the debate initiated by historians of medicine and economic historians with the aim of tracing capitalist traits and market participation in the evolution of health coverage, a process initially promoted by professional doctors who converted their consulting rooms into small clinics and larger hospital companies and which, over time, saw the incorporation of financial capital. In particular, this paper has two specific objectives for the case of Spain. First, to analyse the relationship of collaboration and/or competition between public and private hospitals under democracy and the factors that have conditioned this relationship. Second, to make an initial contribution towards understanding how, in this context, the large private hospital groups have been created in Spain during this period, especially in recent decades with concentration in the hands of financial capital, originating from both the traditional banking sector and investment funds.