most turbulent period since it was forged by a merger a decade ago. Prince resigned five weeks ago after announcing almost $18 billion in write-downs.

Fixing Citigroup will not be easy. Pandit has never run a public company, let alone one as big and complex as Citigroup. The company could face billions of dollars in additional losses on troubled home loans. Its stock price has fallen 40 percent this year, and its balance sheet is overstretched.

Pandit must determine whether the business should be broken up, as investors have prodded for years, or take one last stab at making the company easier to manage. He also must navigate the current market turbulence and chart Citi's overseas expansion.

Pandit is known more as an analytical technocrat than a charismatic leader. He hasnever managed a consumer banking business, an area now besieged by the deepening mortgage-related crisis and a struggling credit-card division. Pandit's candidacy gained strength in recent weeks as investors grew increasingly impatient with Citigroup's search.

John A. Thain, who was approached early on, took the top job at Merrill Lynch after it became clear that the Citi board would not quickly make a decision, according to people briefed on the search.

The selection of Bischoff as chairman was somewhat of a surprise. He has been with Citigroup since it acquired the British bank Schroders in 2000, and had the respect and trust of bank managers. Bischoff, 66, the head of Citigroup Europe, had been seen as a stabilizer when he was appointed to the interim role, and had not been