We assess the quality of opening and closing prices for Nasdaq stocks by examining the effect that opening and closing call auctions (introduced in 2004) have had on price formation. Our use of measurement intervals of one minute or less sharpens the picture of intra-day volatility...

The unmediated call auction is a useful trading mechanism to aggregate dispersed information. Its ability to incorporate information of a single informed insider, however, is less well understood. We analyse this question by presenting a simple call auction game where both auction prices and...