For Wall Street's Math Brains, Miscalculations

By Frank Ahrens
Washington Post Staff Writer
Tuesday, August 21, 2007

They are the powerful, cerebral and offstage actors of Wall Street, but the recent turmoil in the financial markets has yanked them into the light.

They are the math geniuses of the quant funds.

Short for "quantitative equity," a quant fund is a hedge fund that relies on complex and sophisticated mathematical algorithms to search for anomalies and non-obvious patterns in the markets. These glitches, often too small for the human eye, can present opportunities for short- and long-term trades that yield high-profit returns.

The models replace instinct. They try to turn historical trends into predictive science, using elegant mathematics seemingly above the comprehension of your average 401(k) participant or Wall Street fund manager.

Instead of veteran, market-savvy traders waving fistfuls of sell slips, the elite quant funds employ Nobel nerds with math PhDs, often divorced from the real world. It's not for nothing that they are called "black-box" funds -- opaque to outsiders, the boxes contain investment magic understood by only the wizards who conjured it up.

But the 387-point drop in the Dow Jones industrial average Aug. 9 and the continuing turmoil in the markets, in part attributed to massive sell-offs by the quant funds, have tarnished some of the quants' glimmering intellectual credentials and shown that, when push comes to shove, they can rush toward the exits as fast as a novice investor.

Last week, Goldman Sachs said its Global Alpha quant fund had lost 27 percent of its value this year because its computers failed to anticipate what the firm called "25 percent standard deviation moves" or events so rare Goldman had seen them only twice before in the firm's history. On the same day Goldman revealed the bad news, the firm said it would lead a group of big-money investors, including philanthropist Eli Broad, in pouring $3.6 billion into another Goldman quant fund, aiming to shore up confidence in the quants.

Barclays Global Investors, with $450 billion of its $2 trillion in assets under quant management, began applying mathematical tools to its funds in 1978. Last week, Barclays spokesman Lance Berg said the firm was "maintaining its investment process" despite the recent troubles. He would not say how much the Barclays quant funds had fluctuated during the period of turmoil.

The acknowledged quant king is James Simons, 69, an M.I.T.-trained mathematician with a groundbreaking theory that physicists are using to plumb the mysteries of superstring study and get at the very nature of existence itself. Simons turned his big brain on investing after his math career, founding Renaissance Technologies quant shop. The firm pocketed $1.7 billion in investor fees last year, among the highest in the industry. In return, his clients can reap annual returns of more than 30 percent, according to news reports.

As elegant as the models are, they cannot predict unpredictable events, or human panic, some traders say. Further, some say, too many quant funds are full of myopic brainiacs, overly reliant on their tools.

"Most are idiot savants brought to industrial proportion," Nassim Nicholas Taleb, former quant-jock and bestselling contrarian author, said by phone from Scotland, where he is promoting his new book on improbability, "The Black Swan."

"They are very smart in front of a textbook but not smart enough to understand very elementary things in reality," he said.

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