We investigate experimentally whether emotions affect bidding behavior in a first price sealed bid auction. To induce emotions, we confront subjects after a first auction series with a positive or negative random economic shock. We then investigate the relation between affect and bidding behavior in a second auction series. Our main results are: (i) The economic shock has a significant effect on subjects' experienced emotions. (ii) Subjects in a bad mood place significantly higher bids whereas subjects in a good mood do not change their bidding behavior. We interpret our results in terms of risk preferences but also offer an alternative interpretation in terms of probability weighting.