JPMorgan Chase & Co, the biggest U.S. bank by assets, reported a 12.2 percent rise in quarterly profit as revenue from fixed-income trading rebounded.

The bank's net income rose to $5.91 billion, or $1.45 per share, in the first quarter ended March 31, from $5.27 billion, or $1.28 per share, a year earlier.

The results for the latest quarter included an after-tax charge of $487 million for legal expenses.

Analysts on average had expected earnings of $1.40 per share, according to Thomson Reuters I/B/E/S. It was not immediately clear if the results reported were comparable.

JPMorgan shares rose about 2 percent to $63.15 in premarket trading on Tuesday.

Revenue from fixed-income trading rose 5 percent to $4.07 billion, adjusted for the sale of businesses last year, including a physical commodities operation.

JPMorgan's investment bank is the biggest in the world by revenue and ranks at or near the top in market share in almost all of its business lines, according to research firm Coalition.

But the unit is under pressure to cut costs because customers have reduced their trading since the financial crisis and regulators have demanded that big banks take fewer risks, hold more capital and improve controls.

JPMorgan is the first of the large U.S. banks to report quarterly results. Overall, results are expected to show that low interest rates have continued to hold down profits as consumers and businesses refinance loans at lower rates.

Trading picked up early in the quarter after the Swiss National Bank shocked currency markets by scrapping a three-year-old cap on the Swiss franc without warning, causing the currency to soar against the euro.

Non-interest expenses in the bank's investment banking division rose to $5.66 billion from $5.60 billion.

Company-wide expenses, adjusted for legal costs, fell by $402 million to $14.2 billion.

JPMorgan has said it wants to cut annual expenses in its investment bank by $2.8 billion by 2017, excluding legal costs, though some of the savings are expected to be offset by more spending to improve risk controls.