JPMorgan Report Piles Pressure on Dimon in Too-Big Debate

JPMorgan Chase & Co.’s efforts to hide trading losses, outlined in a Senate report yesterday, probably will ignite debate over whether the largest U.S. bank is too big to manage and ratchet up pressure on Chief Executive Officer Jamie Dimon to surrender his role as chairman.

Dimon misled investors and dodged regulators as losses escalated on a “monstrous” derivatives bet, according to a 301-page report by the Senate Permanent Subcommittee on Investigations. The bank “mischaracterized high-risk trading as hedging,” and withheld key information from its primary regulator, sometimes at Dimon’s behest, investigators found. Managers manipulated risk models and pressured traders to overvalue their positions in an effort to hide growing losses.