Solidarity-based finance is a fertile field to analyze the regulation of finance by ethics. However, in a “financiarized” environment, solidarity-based finance runs the risk of losing its solidarity identity by an institutional isomorphism process. Such drift is seen in the case of microfinance in the countries of the South. We identify three forms of microfinance according to the degree of immersion in classical finance environment: pre-banking microfinance (coercive isomorphism case), banking microfinance (normative isomorphism case) and microfinance as a financial asset (mimetic isomorphism case). These different forms of microfinance are modelled through a mathematical formalization. However, this difficulty to join finance and ethics is less driven by an influence of the “financiarized” environment than a deficit of finance collective appropriation. Such a collective appropriation, characterized by actions from the social actors, a strong resilience when faced uncertainty, a strong territorial anchorage and the role of the State, is a particular line of solidarity-based finance in the countries of the North.
