Nicholas Moore, the executive in charge of Macquarie's chief growth engine, will take over as managing director of the group from May when Moss steps down. Moss announced his retirement on the same day as a scheduled operational briefing.One of those two events, or perhaps some other ill-defined rumour, prompted a decline of nine per cent in the group's share price yesterday to $61.10.Moore runs Macquarie Capital, which is a blend of Macquarie's traditional investment banking business and somewhat unconventional specialised managed funds arm, and which accounts for more than 50 per cent of group profits.Moore told a briefing yesterday that "I am not coming in with a change agenda. The organisation has done very well. We expect initiatives to come from our business units. At the centre we evaluate them. That will continue."Allan Moss suggested he had nothing too definite in mind for the next phase of his life but did say it would be "nothing that competes with Macquarie" and "nothing just for the sake of doing something".