We characterise optimal discretionary monetary policy responses to cost-push shocks and to financial distress in the presence of model uncertainty. Under robust control, the central bank reacts more aggressively to both types of shocks, and less to the lagged policy rate, than if the true model...

This paper estimates a business cycle model with endogenous ?rm entry by matching impulse responses to a monetary policy shock in US data. Our VAR includes net business formation, pro?ts and markups. We evaluate two channels through which entry may in?uence the monetary transmission process....

The entry of a new product increases consumer surplus through additional product di- versity but decreases firm profits. In markets where .rm entry intensi.es competition and reduces markups through strategic interactions, we expect entry to be excessively high. In a simple general equilibrium...

Rational expectations models fail to explain the disconnect between the ex-change rate and macroeconomic fundamentals. In line with survey evidence on the behaviour of foreign exchange traders, we introduce model misspecification and learning into a standard monetary model. Agents use simple...

This paper characterises optimal short-run monetary policy in an economy with monopolistic competition, endogenous firm entry, a cash-in-advance constraint and preset wages. Firms must make profits to cover entry costs; thus the markup on goods prices is efficient. However, a distortion results...

Business cycle models with sticky prices and endogenous firm entry make novel predictions on the transmission of shocks through the extensive margin of investment. I test some of these predictions using a vector autoregression with model-based sign restrictions. I find a positive and significant...