Shares of Citigroup fell following news late Monday that Robert Druskin, its head of investment banking, would become its chief operating officer.
Investors are expressing disappointment that the company -- facing criticism over its weak stock price and financial performance -- didn't make more drastic changes.
Citigroup is holding its annual Investor Day meeting on Thursday, when analysts and investors will have a chance to ask company executives about its strategy and outlook.
Druskin, 59, was immediately charged by Citigroup Chief Executive Charles Prince with reviewing the bank's cost base, a major focus of investor criticism. The promotion was seen by some analysts as making him the bank's de facto number two executive.
Druskin, 59, will remain CEO of the commercial and investment banking unit, and will also become chairman of that unit. He will join Prince and Robert Rubin as members of the office of the chairman. All changes are effective Jan. 1.
Investors have been pressuring the top U.S. bank by assets to improve its financial performance for some time. In July, one of the bank's largest shareholders, Saudi Prince Alwaleed bin Talal, called for "draconian measures" to control costs.
Druskin's promotion seemed unlikely to assuage criticism from Alwaleed and others.
"For the time being, the board seems to support Chuck Prince and Chuck Prince has said he remains completely committed to the current business strategy," Howard Mason, a banking analyst with Sanford Bernstein, told CNBC.