NEW YORK (Reuters) - JPMorgan Chase & Co said the U.S. Justice Department was conducting a criminal investigation into its foreign exchange business.

The largest U.S. bank also raised the top end of its loss estimates for legal proceedings, in excess of reserves established, to US$5.9 billion from US$4.6 billion.

The investigation focuses on its spot foreign-exchange trading activities and controls related to those, the bank said in a regulatory filing.

The bank said it was cooperating with the investigations and was in talks with the justice department and civil enforcement authorities, but that there was "no assurance that such discussions will result in settlements."