Enhancing sustainable supply chain management performance through alliance portfolio diversity: the mediating effect of sustainability collaboration.

Purpose: While strategic alliances is a concept increasingly discussed in the field of sustainable supply chain management (SSCM), an emerging and more crucial concept regarding alliances—namely, the alliance portfolio—is mostly ignored in the SSCM context. Mainly drawing on the categorisation–elaboration model (CEM), this research develops a three-layer model to explore the effects of three alliance portfolio diversity facets on the three triple-bottom-line SSCM performances through the mediation of sustainability collaboration. Design/methodology/approach: The field data are collected from 321 Vietnamese manufacturers. Scale accuracy is assessed through the confirmatory factor analysis method. Hierarchical linear regressions are applied to test the proposed model and hypotheses. Findings: Partner, governance, and functional alliance portfolio diversities have a U-shaped, inverted U-shaped, and positive linear effect, respectively, on sustainability collaboration. Sustainability collaboration is in turn found to enhance the SSCM performances in terms of economic, environmental, and social. Originality/value: This research introduced a new theoretical lens, CEM, to the SSCM field. It also provided findings that can help firms to manage their alliance portfolios more dynamically in terms of the nature and diversity level of the portfolio and in a way that adds to the triple bottom line through the mediating effect of sustainability collaboration. [ABSTRACT FROM AUTHOR]