We analyze optimal auction design in the presence of negative externalities. We assume that externalities are a function of both the valuation of the agent who suffers it and the valuation of the agent who obtains the good. This introduces two different sources of countervailing incentives: the...

I consider a model where a principal decides whether to produce one unit of an indivisible good (e.g. a private school) and which characteristics it will contain (emphasis on language or science). Agents (parents) are differentiated along two substitutable dimensions: a vertical parameter that...