For several years I have been developing a theoretical analysis that we have called "socioeconomics of solidarity" and that is linked to other conceptual variants such as "social economy", "community economy" or "social and solidarity economy" as stated in our legal framework. From this point of view, it is a question of highlighting the existence in our "determined markets" of a series of behaviors, experiences and institutions that make use of a rationality and specific alternative instruments to those of homo oeconomicus. In this way, it is possible to think of a specific sector of the economy made up of those actors whose characteristics show notable differences with respect to the private sector and the public sector. This is how the idea of a "third sector" emerged, characterized by making more intensive use of solidarity in the socio-economic field. In our latest published research, we have also noticed the presence of hybrid business formats that open the possibility of thinking about an ideal type scheme of four sectors intervening in the "plural economy". Our elaborations, of wide international diffusion, are based on the sociological confirmation about the emergence of new socioeconomic behaviors that emphasize the recovery of values in the economy, promoting experiences more focused on equity, ecological sustainability, social and gender justice. or democratic participation among others. Thus, numerous concrete experiences are explained, such as fair trade, self-managed production, biological production, food sovereignty, solidarity finance, responsible consumption, etc. On the one hand, our purpose is to survey these behaviors and experiences for their characterization. On the other hand, we build a theoretical framework to be able to account for these phenomena, demonstrating how the common good, shared management, the search for satisfaction of human needs over profit maximization and community values, can lead to successful experiences. of transformative economies. Finally, we also work on a line of research on public policies for the promotion and development of these economies, with special emphasis on legislative matters.