This paper examines the information content of investors' bids in IPO auctions. We discover that investors' bids contain public information known before the auction period. suggesting that investors, on average, condition their bids on public information known before the auction period. We also find that investors' bids contain information relevant to predicting aftermarket returns. The average investors' bidding price can predict aftermarket returns. Institutional allocation also predicts aftermarket returns, suggesting that institutional investors might have better information concerning the value of IPO shares. Finally, we find that our public information variables are relevant to predicting aftermarket returns only insofar as the information has been incorporated in investors' bids.