Daily adjusted prices were extracted from the CRSP tapes from 1970 to 1996. Daily returns were
calculated as simple holding period rates of return between days. Weekly returns were calculated
from Wednesday to Wednesday to avoid any contaminating effects from weekends and Mondays
and end of month prices were used for calculating monthly returns. Daily, weekly and monthly
yields on 3 month T-bills were used for the risk-free rate for the time series regression and the
yield on 12 month T-bills for the dependent variable in the cross-section regressions. T-Bill
yields were calculated at the beginning of the period; for example, for the risk-free rate on
Thursday the closing price/yield on the T-bill on Wednesday was used.