Shares in Citigroup jumped more than 5% after the third largest US bank posted strong profits for the third quarter.
Citi made $2.2bn (£1.4bn) between July and September, above analysts' forecasts and much higher than the $101m profit for the same period last year.
The Wall Street giant, still 12%-owned by the US government after bailouts, cut its provisions for bad debts.
But revenues for the quarter were down almost 6% at $20.7bn.
The revenues were hit by poor performance at the bank's bond and credit derivatives trading business, during a three month period in which markets sold off sharply.
Citi's bad loan provisions of $5.9bn, against $6.7bn in the previous three months, were the lowest since the second quarter of 2007, according to the bank's results.
Losses from bad loans fell by 30% versus a year earlier to $7.7bn, as the level of defaults in Citi's credit card and property operations fell.
Citi's results echo those of fellow US bank JP Morgan, which also reported stronger-than-expected quarterly profits on Friday, also thanks in large part to falling loan loss reserves.
Bank of America - the country's biggest bank - is due to report its results on Tuesday.
"Achieving our third straight quarter of positive operating earnings is continued evidence that we are successfully executing our strategy and we believe we have put in place all the elements for continued profitability," said Citi's chief executive, Vikram Pandit.
The profit figures were ahead of most analysts' forecasts, and mark a third straight quarter of rising profits. Citi's shares opened 3.1% up, sparking a jump in the stock prices of rival banks.
Share prices among big US banks fell heavily last week amid fresh concerns about firms' exposure to the troubled US housing market.
"Financials have tried to weather the storm from the last couple of days, today helped by Citigroup," said Steve Goldman, strategist at US-based broker Weeden & Co.
However Matt McCormick, fund manager at Bahl & Gaynor Investment, said he was concerned about Citi's fall in revenues.
"It's a problem for all the banks now. They have trouble raising revenues," he said.
"Reducing loan loss reserves is not something you can do indefinitely. Eventually, they'll get to the point where they'll say, 'we can't keep going down this path'."
The bank also continued to scale down the overall size of its lending business, with total loans falling 5.5% during the quarter.