A simple approximation of intraday spreads using daily data

This study examines the relation between the bid-ask spread from the daily CRSP data and the bid-ask spread from the intraday TAQ data. We show that the CRSP-based spread is highly correlated with the TAQ-based spread across stocks using data from 1993 through 2009. The simple CRSP-based spread provides a better approximation of the TAQ-based spread than all other low-frequency liquidity measures in cross-sectional settings. However, the CRSP-based spread is highly correlated with the TAQ spread in time-series settings only for NASDAQ stocks. Overall, our results suggest that the simple CRSP-based spread could be used in lieu of the TAQ-based spread in academic research that focuses on cross-sectional analysis.