The decision to replace the chairman gained new urgency last week, when Citigroup announced a drastic plan to split itself in two, effectively undoing the landmark merger that formed the company a decade ago. Citigroup, which lost $8.29 billion during the fourth quarter, plans to sell business that it no longer views as central, and last week said it would split off Smith Barney, its valuable retail brokerage arm, into a joint venture with Morgan Stanley.

Given the turmoil at Citigroup, many analysts and even some Citigroup insiders wonder whether Mr. Pandit can hold on to his job. While Citigroup insists that Mr. Pandit has the full backing of the board, some members have privately expressed some frustration with his leadership.

Regulators have urged Citigroup to create an independent chairmanship and replace several long-serving directors, a move that would enable Citigroup to present a new face to Wall Street. Having Mr. Parsons succeed Mr. Bischoff would give the board more independent oversight. As lead director, Mr. Parsons has been increasing his involvement in Citigroup’s affairs, including meeting with regulators.

As chairman, Mr. Parson said he would “work to reconstitute the board as directors retire with new members who bring strong, proven business judgment and financial and banking sector expertise.”

Several long-serving directors are expected to depart soon. One, Robert E. Rubin, the former Treasury secretary, announced about two weeks ago that he would leave. According to people close to the situation, another director who is likely to leave is C. Michael Armstrong, the former AT&T chairman who led Citigroup’s risk and audit committees from 2004 until last year. Some older directors may voluntarily retire, stepping down as a group to avoid any stigma that they were forced out.