US banking giant Citigroup reported Tuesday third-quarter results that missed expectations, citing a \"challenging\" environment. Citigroup posted net income of $3.2 billion in the July-September quarter, up from $468 million in the same quarter in 2012. Earnings per share came in at $1.00, up from 15 cents a year earlier. Excluding  a tax benefit and CVA/DVA adjustment --the risk-based adjustment of derivative asset valuation -- earnings were $1.02 per share, below the $1.04 analysts estimated. Revenues jumped 30 percent from a year ago, to $17.9 billion, but also came in weaker than the $18.7 billion estimates. Compared with the second quarter, revenues fell 13 percent. Excluding CVA/DVA, the revenues of Citicorp, the bank\'s main division, fell 7 percent from a year ago to $17 billion, and were down 10 percent from the prior quarter. The decline was mainly linked to trading and investment bank activities. Fixed-income revenues slumped 26 percent from a year ago, to $2.8 billion, reflecting lower volumes and uncertain economic conditions, the bank said. \"We performed relatively well in this challenging, uneven macro environment,\" Michael Corbat, Citi\'s chief executive, said in a statement. \"While many of the factors which influence our revenues are not within our full control, we certainly can control our costs, and I am pleased with our expense discipline and improved efficiency year-to-date.\" Citigroup shares were down 1.2 percent at $48.99 in pre-market trading.