The trader may have built a $100 billion position in contracts on Series 9 of the Markit CDX North America Investment Grade Index, according to the people, who said they based their estimates on the trades and price movements they witnessed as well as their understanding of the size and structure of the markets.
The positions, by the bank's calculations, amount to tens of billions of dollars and were built with the knowledge of Iksil's superiors, a person familiar with the firm's view said.