This chapter contributes a distinctive perspective on processes of intermediation by focusing on a particular sub-category of intermediaries: intermediaries of the market. It considers the nature, characterization and affective powers of intermediaries as market agents, involved in processes of competitive market construction and market reconstruction, sitting within socio-technical systems, in relational terms ‘in-between’ processes of production (of goods and services) and their consumption. Importantly, we argue, market intermediaries exert affective powers as change agents on both sides of the production-consumption landscape, providing explanatory leverage on the construction and characterization of both, whilst paradoxically thus far being invisible, in analytical terms, to both the academic and the policy gaze.