Disentangling the complexity of supply relationship formations: Firm product diversification and product ubiquity in the Japanese car industry

The factors and mechanisms that drive the formation of inter-firm supply relationships are complex, and reflect varying strategies that different firms use when building product portfolios. This study aims to disentangle these complex patterns of interactions specifically by focusing on product diversification and product interdependencies in individual firms, as well as product rarity/ubiquity. The empirical data, which captures the formation of supply relationships between carmakers and their suppliers for 200 products, was analyzed using methods developed in the emerging field of network science. The results provided significant insights into how firms’ portfolios vary and interdepend, how firms diversify their portfolios, and how the effect of these may be reflected in the formation of inter-firm relationships.