UPDATE 2-Citigroup sells three credit card portfolios

* Citigroup will service portfolios through 1st half 2010

* Citigroup closes down 4.4 pct (Updates with closing price, spokeswoman no comment)

NEW YORK, Aug 31 - Citigroup Inc said on Monday it sold three credit card portfolios representing $1.3 billion in managed assets, as part of a plan to unload weak businesses and troubled assets that caused huge losses.

The name of the buyers were not disclosed.

The third largest U.S. bank by assets, which did not disclose the terms of the deals, said it will continue to service the portfolios through the first half of 2010.

A Citigroup spokeswoman declined to give further information.

The card portfolios were part of Citi Holdings, a division that includes assets the company is looking to shed or close over time.

In January, Citigroup -- hurt by mounting losses and toxic assets -- decided to separate into Citicorp, housing its key banking business, and Citi Holdings, which included its brokerage, consumer finance, and troubled assets.

The U.S. government injected $45 billion in Citigroup and is the bank's largest shareholder, with a roughly 34 percent stake.

Citigroup's shares ended down 4.4 percent to $5 on the New York Stock Exchange.