In a small room on the banks of the River Thames, on the site of an old dock, Meg Ryan and Jamie Lee Curtis stand in air-conditioned splendour. All day long, they calculate and analyse and send orders to some 17–18 traders sitting outside. No, the American actors have not taken up a second career. Meg and Jamie are the names of two of the computer servers in the headquarters of AHL, part of Man Group, one of the largest hedge fund groups in the world. AHL runs billions of dollars on the back of what those computers decide to do.

In his 1980s novel, The Bonfire of the Vanities, Tom Wolfe said the investment bankers were the “masters of the universe”. That description is now out of date, as Wolfe himself admits. Hedge fund managers have assumed the mantle.

Those men (there are relatively few women) who run the funds have the power to bring down currencies, unseat company executives, send markets into meltdown and, in the process, accumulate vast amounts of wealth. A survey by Alpha, an industry magazine, found that the world’s top ten managers earned almost $10 billion between them in 2008, with the top four taking home – or in their case, several homes – more than $1 billion each.1 Some of the leading managers have become patrons of the art market, helping drive prices of contemporary artists to new highs.

But with this power has come immense controversy. During the credit crunch of 2007 and 2008, hedge funds were accused of exploiting the crisis, driving down the ...

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