Our research empirically assesses two distinct bases for trust: calculative trust, based on a structure of rewards and penalties, versus relational trust, a judgment anchored in past behavior and characterized by a shared identity. We find that calculative trust and relational trust positively influence supplier performance, with calculative trust having a stronger association than relational trust. Yet, important boundary conditions exist. If buyers invest in supplier-specific assets or when supply side market uncertainty is high, relational trust, not calculative trust, is more strongly associated with supplier performance. In contrast, when behavioral uncertainty is high, calculative trust, not relational trust, relates more strongly to supplier performance. These results highlight the value of examining distinct forms of trust.