Considering 91 countries with seaports, this study conducted an empirical inquiry into the broader economic contribution of seaborne trade, from a port infrastructure quality and logistics performance perspective. Investment in quality improvement of port infrastructure and its contribution to economy are often questioned by politicians, investors and general public. A structural equation model (SEM) is used to provide empirical evidence of significant economic impacts of port infrastructure quality and logistics performance. Furthermore, analysis of a multi-group SEM is performed by dividing countries into developed and developing economy groups. The results reveal that it is vital for developing countries to continuously improve the quality of port infrastructure as it contributes to better logistics performance, leading to higher seaborne trade, yielding higher economic growth. However, this association weakens as the developing countries become richer.

In a service exchange setting, the supply management literature generally assumes, with notable exceptions, the availability of complete information regarding supplier reliability. Highlighting the information asymmetry in supplier evaluation and using signaling theory, we argue that for a focal buyer, a supplier's downstream ego‐network instability, that is, other buyers' turnover in a supplier's network from one period to the next, acts as a signal of supplier unreliability, thereby reducing the price that the buyer pays to the supplier in a service exchange. Furthermore, we suggest that focal buyer–supplier relationship strength and structural equivalence weaken the negative effect of instability because the buyer has a more direct and positive experience with the supplier. Using a dataset of 3263 unique dyads formed by 260 buyers (shipoperators) and 493 suppliers (shipowners) during the 2000–2018 period in the container shipping charter market, we find support for our hypotheses, except for the contingent effect of structural equivalence. Our study contributes to signaling literature and network research by developing a supplier's downstream ego‐network instability as a salient heuristic for a focal buyer's pricing decisions. These findings equip buyer managers who may not accurately foresee supplier service quality in the charter market with a new supplier evaluation tool: a supplier's downstream ego‐network instability.