Citigroup Inc on Thursday announced its biggest management shake-up since the financial crisis began, replacing its chief financial officer and installing a new banking chief as it prepares to give the government a 34 percent equity stake.

The changes come as Chief Executive Vikram Pandit faces heavy pressure to improve performance and shed unwanted assets after Citigroup got a series of government bailouts and posted $36 billion of losses in the six quarters ended March 31.

Edward Ned Kelly, who became chief financial officer in March, will become a vice chairman focused on strategy and merger activity.

The new CFO will be John Gerspach, who has been controller and chief accounting officer. He will be Citigroup's fifth CFO in five years.

Citigroup also hired Eugene McQuade, a former chief executive of FleetBoston Financial Corp, as chief executive of Citibank. McQuade was most recently a vice chairman of Merrill Lynch & Co, now part of Bank of America Corp , and is also a former chief operating officer of Freddie Mac .

In other changes, Gary Crittenden, who has been chairman of Citi Holdings, which includes businesses that Citigroup wants to sell or wind down, will leave the bank. He preceded Kelly as CFO.

McQuade is replacing Bill Rhodes as chief executive of Citibank. Rhodes is reducing his responsibilities to focus more on international operations.

In a statement, Pandit said, The senior management changes I am making today will further help in positioning our company for the future. None of the executives was immediately available for further comment.

Citigroup shares closed Wednesday at $2.62.

(Reporting by Jonathan Stempel; editing by John Wallace)