By IANS

New York : In yet another restructuring step at the top level in the Citigroup after taking over as its CEO, Vikram Pandit has promoted Don Callahan, one of his closest associates, to the post of chief administrative officer.

Callahan, who worked with Pandit at Morgan Stanley, takes over from Bob Druskin, who announced last week his retirement as chief operating officer.

He will also oversee marketing and corporate affairs, Pandit said in a memo to Citigroup employees Monday.

Callhan was serving as chief administrative officer at Citi's investment bank and alternative investment division.

Pandit brought him into Citigroup from Credit Suisse on becoming head of this division earlier this year.

Pandit has also asked Lew Kaden, vice-chairman, who was chief administrative officer until September, to remain in his senior role, focusing on corporate governance, strategy, senior recruitment and regulatory and government affairs.

Kaden will also oversee Citi's business in Japan where it has just acquired Nikko Cordial for $13 billion.

Last week, two days after taking over, Nagpur-born Pandit made a bold announcement that Citigroup would assume $49 billion of debt in the US's unravelling home-mortgage credit meltdown.

The decision to bring the so-called structured-investment-vehicles (SIV) onto the company's balance sheets marked a turnaround for the group, which in November had said it would not consolidate the lagging SIVs.

The SIVs represent investments tied to the loans to borrowers with poor credit, the so-called subprime lending practice that has seen tens of thousands of homeowners default on their mortgages.