But these "small, aggressive" traders who rushed to sell were only a handful of people, Ketchum says.

Barings P.L.C. is not the first institution to be shaken by a single, aggressive trader.

Mr. Steinhardt is an aggressive trader who runs a $1.4 billion partnership that bears his name.

Thus, aggressive traders welcome volatility, or what they call implied volatility, the expectation that sudden price changes are likely in the near future.

Sarpy, an aggressive and competitive trader, said that "My object is to do all harm possible to the opposition and yet without harming ourselves."

It lobbied hard for open energy markets and quickly established itself as an aggressive trader in countries like Germany as soon as it had a chance.

Mr. Mulheren was an aggressive and successful trader of the stocks of companies that were takeover targets.

In 1991, the firm was trying to diversify its profit stream by hiring aggressive young traders to help build its Government bond group and other operations.

The Osaka Securities Exchange offers advantages to an aggressive trader, like the one who brought down Barings.

A conservative trader might hold a margin-equity ratio of 15%, while a more aggressive trader might hold 40%.