JPMorgan files formal first-quarter restatement

JPMorgan Chase & Co's international headquarters are seen on Park Avenue in New York July 13, 2012.

(Reuters) - JPMorgan Chase & Co (JPM.N) filed a formal restatement of its first-quarter results on Thursday to reflect its conclusion that the values of derivatives positions on a London trading desk were originally overstated.

The filing took the form of an amended form 10-Q submitted to the U.S. Securities and Exchange Commission. The filing, like the company's July 13 announcement, said first-quarter net income was $4.92 billion, or $459 million less than originally reported.

The reduction reflected a pre-tax loss of nearly $6 billion this year that JPMorgan has disclosed from so-called "London Whale" trades in the company's Chief Investment Office.

(Reporting by David Henry in New York; Editing by Gerald E. McCormick)