JPMorgan Chase & Co, the biggest U.S. bank by assets, reported a rare quarterly loss after incurring $9.2 billion in legal expenses, including money set aside for future settlements.

The bank posted a loss of $380 million, or 17 cents per share, in the third quarter, compared with net income of $5.71 billion, or $1.40 per share, a year earlier.

Excluding litigation expense and reserve release, the company posted a profit of $5.82 billion, or $1.42 per share.

Analysts on average had expected earnings of $1.20 per share, according to Thomson Reuters I/B/E/S. It was not immediately clear if the results were comparable.

JPMorgan's shares were up 1.9 percent at $53.50 in premarket trading.

The prospect of additional legal expenses have been weighing on JPMorgan and CEO Jamie Dimon for more than a year as the company has come under intense scrutiny from regulators following the disclosure of derivatives loss in May 2012.

"While we expect our litigation costs should abate and normalize over time, they may continue to be volatile over the next several quarters," Dimon said in a statement.

JPMorgan shares were up 19.45 percent this year through Thursday to $52.52, lagging the 23.44 percent rise in the KBW bank stock index in the same period.

(Reporting by David Henry in New York and Tanya Agrawal in Bangalore)