Mr. Egol and Fabrice Tourre, a French trader at Goldman, were aggressive from the start in trying to make the assets in Abacus deals look better than they were, according to notes taken by a Wall Street investor during a phone call with Mr. Tourre and another Goldman employee in May 2005.

On the call, the two traders noted that they were trying to persuade analysts at Moody’s Investors Service, a credit rating agency, to assign a higher rating to one part of an Abacus C.D.O. but were having trouble, according to the investor’s notes, which were provided by a colleague who asked for anonymity because he was not authorized to release them. Goldman declined to discuss the selection of the assets in the C.D.O.’s, but a spokesman said investors could have rejected the C.D.O. if they did not like the assets.

Goldman’s bets against the performances of the Abacus C.D.O.’s were not worth much in 2005 and 2006, but they soared in value in 2007 and 2008 when the mortgage market collapsed. The trades gave Mr. Egol a higher profile at the bank, and he was among a group promoted to managing director on Oct. 24, 2007.

“Egol and Fabrice were way ahead of their time,” said one of the former Goldman workers. “They saw the writing on the wall in this market as early as 2005.” By creating the Abacus C.D.O.’s, they helped protect Goldman against losses that others would suffer.

As early as the summer of 2006, Goldman’s sales desk began marketing short bets using the ABX index to hedge funds like Paulson & Company, Magnetar and Soros Fund Management, which invests for the billionaire George Soros. John Paulson, the founder of Paulson & Company, also would later take some of the shorts from the Abacus deals, helping him profit when mortgage bonds collapsed. He declined to comment.

A Deal Gone Bad, for Some

The woeful performance of some C.D.O.’s issued by Goldman made them ideal for betting against. As of September 2007, for example, just five months after Goldman had sold a new Abacus C.D.O., the ratings on 84 percent of the mortgages underlying it had been downgraded, indicating growing concerns about borrowers’ ability to repay the loans, according to research from UBS, the big Swiss bank. Of more than 500 C.D.O.’s analyzed by UBS, only two were worse than the Abacus deal.

Goldman created other mortgage-linked C.D.O.’s that performed poorly, too. One, in October 2006, was a $800 million C.D.O. known as Hudson Mezzanine. It included credit insurance on mortgage and subprime mortgage bonds that were in the ABX index; Hudson buyers would make money if the housing market stayed healthy — but lose money if it collapsed. Goldman kept a significant amount of the financial bets against securities in Hudson, so it would profit if they failed, according to three of the former Goldman employees.