Affiliated Managers Group today reported $241.1 billion in assets under management as of Dec. 31, up 14% from the previous quarter and up 31% from the year before, said spokeswoman Laura Nicoll. The holding company, with stakes in roughly 20 investment management firms, said revenue rose 17% from Sept. 30, and 21% from the year-earlier quarter. In a news release, AMG said investment gains of $12.9 billion and net client inflows of $6.6 billion accounted for almost two-thirds of its asset rise in the quarter. New money management affiliate Chicago Equity Partners accounted for the remainder. For 2006, net client inflows and market appreciation contributed $19.4 billion and $26.4 billion respectively to the company's $57 billion increase in assets under management. For both the quarter and the year ended Dec. 31, institutions accounted for more than 95% of total inflows.