Bids in private value first price auctions consistently deviate from risk neutral symmetric equilibrium bids. It is difficult to explain this deviation with risk aversion. We propose and test two other explanations: (1) Bidders do not form correct expectations. (2) Bidders do not play a best...

In this paper we derive equilibrium bidding functions for first-price and second-price auctions with private values when bidders have outside options. We then study bidding behaviour with the help of experiments. We find that bidders respond to outside options and to variations of common...

First-price auction experiments find often substantial overbidding which is typically related to risk aversion. We introduce a model where some bidders use constrained linear bids. As with risk aversion this leads to overbidding if valuations are high, but in contrast to risk aversion the model...