This qualitative case study explores how situated rationality is achieved and maintained between two coexisting institutional logics, ‘global’ financial efficiency and ‘local’ customer-owners, around a performance measurement system in a large cooperative bank. We focus especially on the relationship between financial performance measures and softer, cooperative and communal organisational values. The results highlight that communal values may be effectively used to smooth and manage managerial contradictions; thus, situated rationality for operations can be achieved and maintained. This may also explain the resilience and success of communal values and cooperatively formed organisations in markets, even though the efficiency of such organisations is sometimes doubted. This also indicates the potential of alternative, more responsible and moderate modes of banking and finance for healing some of the problems of an extreme style of capitalism.