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...

Abstract After suggesting that optimizing equity market structure remains a work in progress (as it has for the past five decades), the paper focuses on liquidity provision – a critical determinant of market quality – and its associations with intraday volatility and price discovery....