We analyze a model of environmental regulation with learning about environmental damages and endogenous choice of emissions abatement technology by a polluting firm. We compare environmental policy under discretion, in which policy is updated upon learning new information, versus under rules, in...

We use a two-period model to analyze the short run and long run profitability and welfare consequences of horizontal mergers, where the equilibrium responses to a merger can differ over time. Although firms can anticipate the merger, they can only adjust their capacity in the long run.We find a...