Relationships between large customers and suppliers expose lenders to additional risks. These risks may force lead agents to retain a larger share of syndicated loans, reducing loan-level diversification, and, in turn, increasing the required interest rate spread. Consistent with this view, we find that borrowers' dependence on a few larger customers or suppliers positively affects the cost of the loans indirectly through the loan structure. Instead, we do not observe a direct cost associated with large customer-supplier links, suggesting that lead agents do not increase the interest rate spread as compensation for the additional risks of dealing with borrowers with large customer-supplier links per se. Finally, we document an inverted U-shaped relationship between the length of the large customer-supplier link and the loan share held by the lead agent. •Lead agent retains a larger share in loans to borrowers with large customer-supplier relationships.•Dependence on large customers or suppliers positively affects the cost of the loans through the loan structure.•The large customer-supplier link is not directly associated to any risk premium.•Inverted U-shaped relationship between the length of the large customer-supplier link and the lead agent's share of the loan.