The Chief Investment Office in London that was responsible for making trades with the bank's excessive cash account may have cost the bank as much as $5 billion making bad bets on derivatives, the newspaper said.
In 2011, executives in charge of the London office decided on a plan to pull back from the risky bets, but the plan was never effectively carried out, sources said.
In April, Chairman and Chief Executive Officer James Dimon called reports of the bets "a tempest in a tea pot." He later said he was "dead wrong" with that assessment.
But in late 2011, CIO head Ina Drew, the head of international trades at CIO Achilles Macris and Peter Weiland, the chief risk officer of the office, agreed the derivative bets should be reduced, sources said.
It was not the first time big risks at the London office caught the eye of bank executives. In 2010, the CIO chief financial officer at the time, Joseph Bonocore, raised the alarm about $300 million lost in a few days without a complimentary, offsetting position to keep the bets balanced.
Bonocore took the matter to the bank's chief risk officer at the time, Barry Zubrow, and JPMorgan Chief Financial Officer Michael Cavanagh.
The executives gave Bonocore permission to reduce the bets. In turn, Macris reduced those bets, the newspaper said.
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