# Why Fama and French sort on June's size data and not of some other period?

In Fama and French (1993), p. 8, I read "In June of each year $t$ from 1963 to 1991, all NYSE stocks on CRSP are ranked on size (price times shares)."

Later on the same page, they write "Book-to-market equity, $BE/ME$, is then book common equity for the fiscal year ending in calendar year $t-1$, divided by market equity at the end of December of $t-1$."

December seems fine: a year ends in December. But why do they choose June and not December, too, for the size?

• In the stock market everything gets slower around June. For a long period over summer. Maybe it's a natural choice? May 8 '16 at 17:22