Those levels are fairly low compared with other banks that have been in distress recently. Protecting $10 million of Wachovia's debt against default just before it agreed to sell itself would have cost $1.49 million a year.

The comparatively low cost to protect Citigroup's debt combined with the low share price signal that markets expect the company to raise large amounts of preferred or common equity, potentially with government help.

But the cratering stock price, on top of the job cuts, had employees on edge. "Now I know what the people at Lehman Brothers felt like," a bank staffer said, referring to the investment bank that filed for bankruptcy protection on Sept. 15.

Gustavo Dolfino, president of recruiting firm WhiteRock Group, said he had been receiving more calls from employees at the managing-director level at Citigroup in recent days.

"I've spoken to a number of people that are very concerned about their jobs and the bank's survival," Dolfino said.

On Thursday, Saudi Prince Alwaleed bin Talal said he planned to increase his stake in Citigroup to 5 percent from less than 4 percent. The bank's largest individual investor called Citigroup's shares "dramatically undervalued."