In an account on his website, Iksil, a French national who traded credit derivatives for JPMorgan in London, also blamed senior executives at the bank. (http://bit.ly/2sjf2WS)

"The senior executives chose Iksil to work as a screen for them in late 2010", he said.

The Chief Investment Office (CIO), where Iksil worked, lost $6.2 billion in trading in 2012, hurting the bank's reputation.

"When the CIO of JPMorgan had lost $1 billion dollar, JPMorgan as a whole had made $4 billion for itself net of its CIO loss," Iksil alleged.

"The JPMorgan CIO lost in whole $6.3 billion which led to an ultimate profit at JPMorgan of more than $25 billion in 2012," he said on the website.

The bank had to pay more than $1 billion and admit to wrongdoing to settle U.S. and British probes into the losses.

JPMorgan declined to comment.

(Reporting by Arunima Banerjee in Bengaluru; Editing by Sriraj Kalluvila)