The Most-Favored Nation (MFN) clause has long been suspected of creating a free rider problem in multilateral trade negotiations. To address this issue, we model multilateral negotiations as a mechanism design problem with voluntary participation. We show that an optimal mechanism induces only...

Using an aggregative games approach, we analyze horizontal mergers in a model of multiproduct-firm price competition with nested CES or nested logit demands. We show that the Herfindahl index provides an adequate measure of the welfare distortions introduced by market power, and that the induced...