We consider two ascending auctions and show that many of the (unwanted) collusive or signaling equilibria studied in the literature in the framework of the SEAMO (simultaneous English auction for multiple objects) don't have a counterpart in the JAMO (Japanese auction for multiple objects). We...

We compare the seller's expected revenue in a second price sealed bid auction for a single object in which bidders receive multidimensional signals. Bidders' valuations for the object depend on their signals and a signal observed privately by the seller. We show in various examples that the...