The testimony of arbitrageurs (in, for example, my interview with David Shaw) is that in addition to the anomalies discussed in the literature of financial economics that are exploitable market inefficiencies that are not publicly known. Naturally, arbitrageurs are reluctant to say exactly what they are: others' exploitation of them would very likely reduce or eliminate them. Even in 1965 it was clear to James Lorie, founder of the Center for Research in Security Prices, that such anomalies might exist: ". . . there is a haunting fear that those with the best arguments [against the random-walk hypothesis] are silently sunning and swimming at St. Tropez" (Lone 1965, p. 18).

Donald MacKenzie, An Engine, Not a Camera, loc. 457