Swimming against the tide: supplier bridging roles in diffusing sustainability upstream and downstream in supply networks

Purpose This paper aims to investigate the bridging role of first-tier suppliers in diffusing sustainability in supply networks and how this role is facilitated by the procurement function. Design/methodology/approach The paper is based on an embedded case study of two supply networks of a coffee beans roasting company. The embedded cases focus on coffee beans and packaging supply networks. Findings The findings reveal less than expected involvement of the focal company and its procurement function in sustainability implementation with first-tier suppliers. Instead, sustainability diffuses upstream to lower-tier suppliers but also downstream, against the tide, as a result of the various bridging roles performed by first-tier suppliers. Research limitations/implications This paper provides two theoretical contributions. First, it contributes to the sustainable supply network management literature by providing rich insights on sustainability diffusion to lower-tier suppliers and the role of first-tier suppliers in this process. Second, the paper contributes to structural hole theory by revealing a typology of bridging roles that actors, such as suppliers, undertake in the sustainability context. Practical implications The paper provides managers with practical insights on how sustainability can be diffused in the supply network and the different roles that first-tier suppliers can play in this direction. Originality/value This paper shows that sustainability diffusion to lower-tier suppliers is possible in the absence of focal company procurement involvement when bridging roles are undertaken by first-tier suppliers and their procurement functions are involved in the implementation process. These bridging roles facilitate sustainability diffusion both upstream and downstream.