In this paper we explore the relationship between knowledge, trust, and space in the production and consumption of retail financial services as part of a wider enquiry into processes of financial exclusion. We argue that the relationship between knowledge and trust helps to explain the evolution of financial services and the production over time of distinctive ecologies of financial service production and use. We discuss the changing scales of financial knowledge and trust in relation to the evolution of the UK financial services industry. We identify two idealised ecologies and networks of retail financial services. The middle-class suburb represents an ecology and network of privilege within the contemporary retail financial services market. It displays relatively high levels of aggregate knowledge about the financial system and constitutes an important part of the retail financial services network, with strong and frequent connections to the financial services industry as a whole. Poor inner-city areas and peripheral local authority housing estates, meanwhile, have very different financial ecologies. Areas of relative deprivation and poverty, they constitute 'relic' financial ecologies that have been bypassed and mostly ignored by the mainstream financial services industry. They are colonised by a distinctive set of financial institutions that include firms that operate door-to-door. We look at the formation and evolution of these ecologies over time and discuss the potential of enriching the ecology of the poor inner-city and peripheral local authority housing estate through public policy.