An auction is externality-robust if unilateral deviations from equilibrium leave the other bidders' payoffs unaffected. The equilibrium and its outcome will then persist if certain types of externalities arise between bidders. One example are externalities due to spiteful preferences, which have...

For the procurement of complex goods the early exchange of information is important to avoid costly renegotiation ex post. We show that this is achieved by bilateral negotiations but not by auctions. Negotiations strictly outperforms auctions if sellers are likely to have superior information...

We compare two commonly used mechanisms in procurement: auctions and negotiations. The execution of the procurement mechanism is delegated to an agent of the buyer. The agent has private information about the buyer's preferences and may collude with one of the sellers. We provide a precise...

Recent literature has shown that all-pay auctions raise more money for charity than winner-pay auctions. We demonstrate that the first and second-price winner-pay auctions generate higher revenue than first-price all-pay auctions when bidders are sufficiently asymmetric. To prove it, we consider...