This paper analyses the development of pseudo micro-profit centres (MPCs) at Kitanihon, a Japanese manufacturer. MPCs aim to relate financial and operational concerns by sensitising operators to the financial consequences of their actions and by triggering financial improvements. MPCs, however, also create many small interdependent responsibility centres, which makes it difficult to delegate financial accountability. The paper studies the dynamic construction of relations between financial and operational concerns when structural interdependencies are important. It analyses such construction as a process of mediation. While extant studies focus on how accounting calculations, as mediating instruments, help linking dispersed people, aspirations and domains, the paper studies how accounting requires itself to be mediated to relate financial and operational concerns and to become powerful. It shows that people, spaces and instruments form a heterogeneous ‘web of mediators’ by which relations between accounting and operations are constructed. It shows how structural interdependencies take part in this mediation of relations. Finally, this study shows that mediation does not link, but transforms mediated entities including accounting, which forms, per-forms and trans-forms along the chain of mediation it helps constituting.