Belief-free price formation.

Summary We analyze security price formation in a dynamic setting in which long-lived dealers repeatedly compete for trading with potentially informed retail traders. For a class of market microstructure models, we characterize equilibria in which dealers’ dynamic pricing strategies are optimal no matter the private information each dealer may possess. In a generalized version of the Glosten and Milgrom model, these equilibria deliver price dynamics reminiscent of well-known stylized facts: price/trading-flow correlation, volatility clustering, price bubble and inventory/inter-dealer trading correlation.