As a general principle, state aid to firms and sector-specific support schemes should be used only when there are market failures; that is, when there are good reasons to believe that the market would not deliver efficient and/or equitable outcomes.

It has been suggested that mergers, by increasing concentration, raise incentives to invest and hence are pro-competitive. To study the effects of mergers, we rewrite a game with simultaneous price and cost-reducing investment choices as one where firms only choose prices, and make use of...