The secrecy of the negotiations and the price paid stunned the City into awed silence. Merrill Lynch's takeover was certainly a good deal for Mercury Asset Management's shareholders. But was Merrill so taken with the brand name that it underestimated the fund manager's problems? Mercury has little room for growth at home and has never had much success expanding abroad. Mercury wants to keep some independence, but how long before it gets Merrillized? Antony Currie reports.