JPMorgan Chase & Co. is paying $920 million US in penalties and admitting wrongdoing over a $6 billion trading loss last year that tarnished the bank's reputation.

Regulators say weak oversight at the largest U.S. bank enabled traders in its London operation to assign inflated values to trades and cover up losses as they ballooned.

The combined amount JPMorgan is paying is one of the largest fines ever levied against a financial institution.

The regulators said JPMorgan failed to properly supervise the traders, two of whom face criminal charges of falsifying records to hide the losses.

Javier Martin-Artajo, 49, and Julien Grout, 35, and their co-conspirators were accused of marking up the market value of an investment portfolio to hide the fact that it was plummeting in value. The portfolio eventually sank into an eye-popping $6 billion loss attributed to Bruno Iksil, a trader who became known as the "London Whale" for his location and the supersized bets he made.

The Securities and Exchange Commission, the Office of the Comptroller of the Currency, the Federal Reserve and Britain's Financial Conduct Authority joined in sanctioning the bank.