Environmental Taxation and Mergers in Oligopoly Markets with Product Differentiation

We analyze the effect of mergers on optimal environmental taxation in a Cournot oligopoly market with product differentiation. Our result indicates that the adjustment in emission tax crucially depends on the post-merger output distortion and pollution intensities. Specifically, we find that the optimal emission tax increases post-merger as long as pollution intensity of firms is higher and output distortion smaller post-merger than pre-merger. Furthermore, our result suggests that there is no need to revise environmental policy in markets where pollution intensity of firms does not change post-merger and (i) products are completely differentiated, or (ii) there are many firms for any degree of product differentiation.