In many emerging countries, firms face formal institutional voids that raise both the cost and the level of difficulty of business operations. In this study, we examine a unique culture-rooted mechanism that may address those voids, and this comes in the form of supply chain partner surname sharing based on the legacy of clan identification. Using a unique Chinese dataset that was manually collected and merged from multiple sources, we find that firms registered in the region with a stronger clan culture are more likely to cooperate with supply chain partners with the same surname. This positive effect of clan culture is negatively moderated further by the level of subnational marketization. Therefore, we shed new light on the supply chain-level implications of clan culture, an Asian cultural-specific topic that has received little attention in marketing and supply chain literature. •A firm located in the region with a stronger clan culture will more likely trade with supply chain partners (both suppliers and clients) with the same surname.•The positive association between clan culture and partner surname sharing is stronger in areas with poorer levels of formal institutional development (i.e., low marketization).