Citigroup Inc, the fourth-biggest U.S. bank by assets, reported a 10.5 per cent fall in quarterly profit on Friday, hurt by lower revenue from equity trading.

The bank's net income fell to US$3.84 billion, or US$1.24 per share, in the third quarter ended Sept. 30 from US$4.29 billion, or US$1.35 per share, a year earlier.

Total adjusted revenue fell 4 per cent to US$17.76 billion.

Analysts on average had estimated earnings of US$1.16 per share. It was not immediately clear if the results were comparable.

Equity markets revenue fell about 34 per cent, driven by lower market activity.

In the year-earlier quarter, the bank recorded a gain of US$180 million on the sale of a business in Mexico and a US$140 million valuation adjustment in its equity markets division.

Citigroup, the most international of the large U.S. banks, has been exiting less-profitable operations in markets around the world, consolidating back offices and cutting jobs to become leaner.

Adjusted revenue from Citicorp, the bank's core business, rose 0.6 per cent to US$16.88 billion, while expenses rose 3 per cent to US$9.58 billion.

Earlier on Friday, JPMorgan Chase & Co reported a 7.6 per cent drop in quarterly profit after recording a tax expense, compared with a rare tax benefit a year earlier, but both revenue and profit beat analyst estimates.