Strategic bidding in a private value experimental auction with positive and negative bids

We treat a difference in initial bids for two private goods as an endogenous “induced” value. Results from follow up auctions eliciting positive or negative bids to exchange one good for the other suggest that positive WTP bids are demand revealing while subjects tended to overbid (in absolute value) negative WTA values. Controlling for risk attitude in WTA bids is shown to partially explain the WTA overbidding. WTA bids tended to be lower in a random nth price auction compared to those elicited in a 5th price auction.