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.