(Recasts paragraphs 1, 4; adds Pandit comments, other banks and closing prices in paragraphs 8-11)

By Jonathan Stempel

NEW YORK, Jan 14 (Reuters) - Citigroup Inc (C.N: Quote, Profile, Research) faced growing uncertainty on Wednesday about whether it will rebound from punishing losses, as investors drove the stock below $5, its lowest level since a government rescue in November.

More bad news is expected on Friday, when the bank plans to report quarterly results, six days ahead of schedule, and analysts are looking for a fifth straight multibillion-dollar loss. The bank is also widely expected Friday to provide details of a comprehensive downsizing designed to ensure its survival.

Rival JPMorgan Chase & Co (JPM.N: Quote, Profile, Research) also moved up its earnings report by six days to Thursday.

Once the world's largest bank, but now No. 3 in just the United States, Citigroup is expected to shrink by about one-third as it focuses on corporate, investment and retail banking and trims trading operations, a person familiar with the plan said.

Citigroup will also put unwanted businesses and assets into a separate structure, with an eye toward their eventual sale, the source said.

The U.S. Treasury Department has pumped $45 billion of taxpayer funds from the Troubled Asset Relief Program (TARP), including $20 billion on Nov. 23, when the government agreed to a bailout, sharing in bank losses in exchange for preferred stock and warrants.

The bailout helped avoid a collapse on the heels of the Lehman Brothers Holdings Inc's (LEHMQ.PK: Quote, Profile, Research) bankruptcy on Sept. 15.