We analyze price competition between dealers in a security market where the bidding process is sequential. The model provides an interpretation for the evolution of the best ask and bid prices, in between transactions. We find that convergence to the competitive ask and bid prices can take time. The speed of convergence is determined by the frequency with which dealers check their offers and by the tick size. This creates a relationship between the expected trading cost and the timing of offers posted by the dealers. We also find that a zero minimum price variation never minimizes the expected trading cost. Finally, we study the role of time priority. Journal of Economic Literature Classification Numbers: D43, G10.

The traditional approach to the central bank's lender of last resort function emphasizes the trade-off between being too ‘tough’, and thus increasing the likelihood that the failure of a single bank hampers the confidence in the whole banking system, and being too ‘soft’, thereby creating incentives for banks to take on excessive risk. In contrast with this view, we show that a central bank, by announcing and committing ex-ante to bail out insolvent institutions in times of adverse macroeconomic conditions, can create a risk-reducing ‘value effect’ that outweighs the moral hazard component of the policy, and thus lowers bank risk.