Business Photo Slideshows

The Calgary Cowboy

Photo by Adam Rountree/Bloomberg News/Landov

Amaranth Advisors was a hedge fund based in these offices in Greenwich, Connecticut. But bets on natural-gas prices made by Brian Hunter, a trader operating out of Calgary, Canada, went bad in 2006. The fund lost $6 billion and was forced to unwind. Regulators have accused Hunter of trying to manipulate prices. Hunter, who is starting up his own hedge fund, has denied any wrong doing.

The Phantom

Photo by AP Photo/Adam Nadel

Kidder, Peabody fired bond trader Joseph Jett in 1994, accusing him of generating phantom trades that appeared to show $350 million in profits. Jett did so, the firm said, in an effort to inflate his compensation. But the trades actually created losses, and the scandal prompted General Electric to sell the Wall Street firm.

Mr. 5 Percent

Photo by AP Photo/Kyodo News

Yasuo Hamanaka, was such a powerful trader in copper that he was was known as "Mr. 5 Percent" for the share of the global market he was believed to contol. When it was disclosed in 1996 that unauthorized trades by him cost Sumitomo $2.6 billion in losses, copper prices plunged nearly $1,000 a tonne. Hamanaka was convicted of fraud and sentenced to eight years in prison.

The Cover-Up

Photo by Chris Kleponis/Bloomberg News/Landov

John Rusnak, second from right, was a currency trader at a Baltimore subsidiary of an Irish bank, and was facing large losses. Through fictitious trades and fake confirmations, he hid five years' worth of losses, or $691 million, before his scheme was uncovered in 2002. He was sentenced to seven and a half years in prison.

The Man Who Broke Barings

Photo by JOHN MACDOUGALL/AFP/Getty Images

There have been few collapses as spectacular as that of Barings, a venerable British investment bank, in 1995. Nicholas Leeson, then a 28-year-old futures trader, bet an unauthorized $29 billion of the bank's money on Japanese stock and bond markets. He lost $1.4 billion of it. After leaving prison, Leeson wrote a book and is now chief executive of the Galway United Football Club in Ireland.