The third-largest U.S. bank said the loss amounted to 33 cents a share, compared with a loss of $17.3 billion, or $3.40 a share, in the same quarter a year earlier.
The loss matched analysts' average estimate, according to Thomson Reuters I/B/E/S. Citigroup shares were unchanged in premarket trading at $3.42.
The bank set aside $8.2 billion in the quarter to cover bad loans and other losses, down 36 percent from a year earlier.
Citigroup is the second major U.S. bank to report fourth-quarter results. JPMorgan Chase & Co
Citigroup has been struggling to return to profitability in its main lending businesses after posting more than $100 billion of credit losses and writedowns. Although the bank posted a profit for 2009, $6.7 billion came from selling a controlling stake in its Smith Barney business.
Citigroup shares fell more than 50 percent in 2009, while the KBW Bank index <.BKX>, a broader measure of banks, fell 3.6 percent.
(Reporting by Dan Wilchins; editing by John Wallace)