Citigroup Inc got a call from a prominent investment banker suggesting a merger with Bank of America Corp as it was dealing with billions of dollars in mortgage-related losses and the departure of Chief Executive Charles Prince, the Wall Street Journal reported Wednesday in its online edition.

Citigroup's board dismissed the informal approach as totally out of hand and no discussions have taken place, the Journal said, citing a source familiar with the matter.

Bank of America, meanwhile, said it never authorized a formal proposal to Citigroup, according to the Journal.

A person familiar with the matter said Citigroup's board would be unlikely to view a merger with Bank of America favorably, as the past few months have shown the bank is difficult to manage, the Journal said, adding combining it with another giant would exacerbate the problem.

A source told the Journal that Citigroup got a feeler from Bank of America several months ago.

Representatives of both banks could not immediately be reached for comment.

Earlier this week, Citigroup sold up to 4.9 percent of itself for $7.5 billion to the Gulf Arab emirate of Abu Dhabi, giving it fresh capital as it wrestles with the subprime mortgage crisis.

Abu Dhabi will be Citigroup's largest shareholder.

(Reporting by Justin Grant; Editing by Paul Bolding)

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