Sandy Weill, the highest paid banker in the world, and John Reed, the groups co-chairmen, have been in London this week talking to heads of department in Europe about options for growing their business areas. They have let it be known that expansion is the top priority.
Names of potential partners that have surfaced internally include HSBC, which recently bought Edmond Safra's Republic Bank of New York in the US for $10bn, and Spain's BSCH. However, it is far from clear that either would agree to a deal.
Other possibilities could include Barclays, which, with Matt Barrett, its new Canadian chief executive, coming on board next month is thought likely to be receptive to the idea of a trans-Atlantic merger deal.
Staff at Salomon Smith Barney, the investment bank owned by Citigroup, have also heard gossip that Schroders, Cazenove and even Warburg might also be on Mr Weill's hit list. British bankers have long felt that a major strategic move in the UK by Citigroup was only a matter of time.
"There is definitely talk that Sandy is itching to write a cheque," said one insider. "Others would prefer the group to grow organically but there is no doubt that he is a deal man."
Mr Weill has been one of the most aggressive consolidators in the American financial services industry steering Travellers, the US insurance giant, to a merger with Citicorp last year. The group has a strong presence in both Latin American and Asia, but despite a recent sales push in the UK has yet to crack the European retail market. It is also one of the most profitable corporations in the world, having racked up profits of more than $2bn for the past two quarters.
Another insider said: "If we get to the end of the year and don't make some form of announcement, I would be very surprised. Sandy wants asset management; we want the UK. The question is: `do we want to grow organically or will we get there quicker if we acquire'?"