.Finally, we analyze how dealers’ connectedness and the efficiency of interdealer trans-actions affect trading costs for dealers’ clients (end-investors). To this end, we introducea trading round between dealers and clients before interdealer trading. We show thatconnected peripheral dealers charge smaller bid-ask spreads than unconnected dealers be-cause they obtain a higher expected profit on interdealer transactions, both because theycan manage inventory costs more efficiently and obtain larger rents. Moreover, the differ-ence between the bid-ask spreads charged by unconnected and connected dealers increaseswhen more dealers become unconnected, which suggests that dealers’ connectedness is adeterminant of the dispersion in bid-ask spreads observed in OTC markets. Relatedly, thedifference between equilibrium transaction costs for dealers’ clients and those that wouldbe obtained if trades were conducted efficiently among dealers (the first best allocationof inventories among dealers) is inversely related to the level of connectedness betweenperipheral and core dealers.