Back in 1967 a man calling himself Adam Smith wrote a wonderful book called The Money Game. Smith — actually a professional investor called George Goodman writing under a pseudonym — devotes one chapter to what he called “The Cult of Performance”. In it, he describes the shift that took place in fund management in the 1960s.
Before then, portfolio management was not an “Instrument of Personality”. Funds were instead run by a “Prudent Man” — the kind who “died with an estate that won the admiration of the lawyers for its order and efficiency”.
His portfolio had around 200 stocks in it — the 200 biggest companies in the US. These made up two-thirds of the assets — bonds made up the rest.