When U.K. Chancellor of the Exchequer George Osborne officially opened Man Group’s new City of London office in July 2011, not long after cutting the ribbon at a similar ceremony for Japanese bank Nomura, he joked, “When I did this at Nomura, the whole thing almost fell down.” Happily, both buildings still stand, but, less happily, both firms are now in crisis. Man’s CEO for the past five years, Peter Clarke, said on December 10 that he will be stepping down in February after more than a year of capital outflows and disappointing performance. It’s not clear, however, how CEO-designate Emmanuel (Manny) Roman, the president and COO, can turn things around.

“A change of leadership is unlikely to have a material, near-term impact in itself,” says Peter Lenardos, a financial services analyst at RBC Capital Markets in London. “Man needs to continue to focus on fund performance, gathering assets and ensuring that its funds are fairly priced from a competitive point of view.”....