We provide a theory of trading through intermediaries in over-the-counter markets. The role of intermediaries is to sustain trade. In our model, traders are connected through an informational network. Agents observe their neighbors’ actions and can trade with their counterparty in a given period through a path of intermediaries in the network. Nevertheless, agents can renege on their obligations. We show that trading through an informational network is essential to support trade when agents infrequently meet the same counteparty. However, intermediaries must receive fees to implement trades. Concentrated intermediation, as represented by a star network, is both constrained efficient and stable when agents incur linking costs. The center agent in a star can receive higher fees as well.

The Lagos‐Wright model—a monetary model in which pairwise meetings alternate in time with a centralized meeting—has been extensively analyzed, but always using particular trading protocols. Here, trading protocols are replaced by two alternative notions of implementability: one that allows only individual defections and one that also allows cooperative defections in meetings. It is shown that the first‐best allocation is implementable under the stricter notion without taxation if people are sufficiently patient. And, if people are free to skip the centralized meeting, then lump‐sum taxation used to pay interest on money does not enlarge the set of implementable allocations.