This chapter explores the relationship between trust and social change. It presents a process view on trust based on interactionism and classic sociology combined with a grounded theory methodology. Development and maintenance of trust – trusting – is a dynamic and multi-level process of social construction, a process of sensemaking based on interplay between pre-contractual, relational and structural social bases. Mutual understanding is the engine of the trust process. Mutual understanding triggers the leap of faith from doubt into trusting. The chapter analyses how changes in economic organization on the macro level – deregulation – can transform a trust relationship on the micro level – here between savings bank and customer. Social changes on the macro level influence trust relationships on the micro level; deregulation transforms the social bases for trust between savings bank and customer, and trust is lost and then restored. Social change is changes in the social bases for trust. This study is not about testing a hypothesis, but explores social processes and grounds theories and concepts in empirical findings. Focus is on the social foundation of trusting and the social construction of mutual understanding, which is an unexplored perspective in trust research. The chapter aims to reduce this gap of knowledge.