Revenue-Maximizing Auctions : A Bidder’s Standpoint

We address the problem of improving bidders’ strategies in prior-dependent revenue-maximizing auctions and introduce a simple and generic method to design novel bidding strategies if the seller uses past bids to optimize her mechanism. We propose a simple and agnostic strategy, independent of the distribution of the competition, that is robust to mechanism changes and local (as opposed to global) optimization of e.g. reserve prices by the seller. This strategy guarantees an increase in utility compared to the truthful strategy for any distribution of the competition. We generalize this result by showing that a best response, reaching the best tradeoff between beating the competition and reducing the reserve price in a large class of possible strategies, is a simple extension of this first strategy. Our new variational approach naturally yields itself to numerical optimization and algorithms for designing or improving the strategies in any given selling mechanisms. Our formulation enables to study some important robustness properties of the strategies, showing their impact even when the seller is using a data-driven approach to set the reserve prices. In this sample-size setting, we prove under what conditions, optimal bidding strategies can still improve the buyer’s utility. The gist of our approach is to see optimal auctions in practice as a Stackelberg game where the buyer is the leader, as he is the first one to move (here bid) when the seller is the follower as she has no prior information on the bidder