Our sample selection starts from all firms with December fiscal year-end from 1951 to 2005, with available return data
in the CRSP monthly file and accounting data in the Compustat annual database. The December fiscal year-end requirement avoids misspecifications due to different reporting periods. The annual return for each firm is measured by
cumulative return from April of year t through March of year tþ1. Our basic earnings change measure for each firm is the
change in income before extraordinary items, scaled by market value at the beginning of the fiscal period. For each year,
we exclude stocks with the beginning-of-period price per share below $1. We also exclude the top and bottom 5% of firms
based on earnings changes. Finally, we exclude firms with negative book values. The average number of stocks per year is
about 1320 in our sample, increasing from 220 in 1951 to 2865 in 2005.