Citigroup's options dwindle as shares under $4

"A merger is indeed a possibility at this point," Fitzpatrick said. He said there are a number of firms that would be eager to take over some of Citigroup's businesses — particularly a company like Goldman Sachs Group Inc., an investment bank that recently turned into a bank holding company and is now on the prowl for deposits.

Citigroup is considered the most vulnerable among the major U.S. banks, failing to turn a profit in the past four quarters when rivals such as New York-based JPMorgan Chase & Co. and Charlotte's Bank of America Corp. managed to do so.

Concerns are growing that the deteriorating economy and still-turbulent markets will slam Citigroup with more write-downs in the coming quarters. What began as a subprime residential mortgage crisis has ballooned into a full-blown debt crisis, escalating defaults in everything from leveraged loans to credit card debt to commercial real estate loans.

The bank has been rushing to get leaner and wind down its assets backed by risky debt. Monday, Citigroup said it will cut 53,000 jobs, on top of 22,000 cuts previously announced. On Wednesday, the bank said it is acquiring the remaining $17.4 billion in assets held by complex debt products known as structured investment vehicles that it previously ran off its balance sheet.

A call that CEO Vikram Pandit and Chief Financial Officer Gary Crittenden held Friday morning with senior managers at the bank offered nothing new about a shift in strategy for the company.

People familiar with the call, who spoke anonymously because the comments during the call were not made public, said that Pandit's message was similar to that at his town hall meeting with employees on Monday — that Citigroup has adequate capital, and that he supports the universal bank model.

Still, the people said the call, which lasted about half an hour, did not rule any option out.

"It's clear everything is on the table. That wasn't explicit, but I think it's clear," one person said.