“…14 Of the databases created during the 1960s, one of the most important was set up by the Graduate School of Business at the University of Chicago, 15 one of the key institutions 13 By defi nition, a martingale model, 1 ( ) 0 t t t E P P + Φ − = , Φ t, is a fi lter-that is, to use the terminology of fi nancial economics, a set of information that increases over time. 14 See, for instance, Cohen and Pogue ( 1967 ). 15 In 1960, two University of Chicago professors, James Lorie and Lawrence Fisher, started an ambitious four-year program of research on security prices.…”