Increasingly, those who appeared to be active, risk-taking, stock-picking managers (and who charged the corresponding high fees) were in fact "closet indexers." Becker Securities regularly tracked the beta values of a sample of apparently actively managed portfolios relative to the S&P 500 index. A portfolio that tracked the index exactly would have a beta of precisely 1.0. From 1967 to 1971, the median beta was 1.09, indicating the taking on, on average, of somewhat more than simply overall market risk. By the end of 1974, the median beta was down to 1.07, and at the end of 1976 it was a mere 1.02 (Welles 1977, p. 51).

Donald MacKenzie, An Engine, Not a Camera, loc. 383