Microfinance serves as a key case for studying the effects of financial systems. As a development intervention deeply intertwined with processes of financialisation, we study the expansion and workings of microfinance on three dimensions. First, microfinance’s appeal is built on positive mobilising narratives which present poverty as a problem of finance, and portray it as superior solution relative to charity or other redistributive alternatives. Second, microfinance as a financial system exerts a governmentality which works through technologies of the selffor disciplinary individuals to uphold regularity in capital flows. Third, in this way microfinance makes possible the extraction of surplus value from its poor borrowers, who may not have much choice, at a considerable scale. We conclude that these three dimensions help to explain the ways in which financial systems overall operate and expand.