This paper provides a framework for addressing the question of when transactions should be carried out within a firm and when through the market. Following Grossman and Hart, we identify a firm with the assets that its owners control. We argue that the crucial difference for party 1 between...

We analyze bidder collusion in public procurement. Our focus is on less than all-inclusive cartels. We use public information on convicted bid-rigging schemes taken from the decisions of the French Competition Authority to tackle the question of external cartel stability. Our goal is to...

There are two parts to this paper. Part One introduces the subject of implementation, and provides applications (in particular, to the theory of contracts). This part is written so as to be accessible to the general reader. Part Two surveys the literature, and is somewhat more formal.