This paper demonstrates theoretically and experimentally that in first-price auctions overbidding with respect to the risk neutral Nash equilibrium might be driven from anticipated loser regret (felt when bidders lose at an affordable price). Different information structures are created to elicit regret: bidders know they will learn the winning bid if they lose (loser regret condition); or the second-highest bid if they win (winner regret condition); or they will receive no feedback regarding the other bids. Bidders in loser regret condition anticipated regret and significantly overbid. However, bidders in the winner regret condition did not anticipate regret.

In Brock, Lange, and Ozbay (2013), we experimentally investigate social preferences under risk. One of our conclusions is that a social preference model incorporating both ex ante and ex post fairness concerns may best describe behavior. Krawczyk and Le Lec (2016 ) argue that ex ante comparisons alone may account for our data. We address their points in this reply.