EXHIBIT 21.1 LIST OF SUBSIDIARIES (in alphabetical order) WHOLLY OWNED SUBSIDIARIES OF THE REGISTRANT AMG/TBC Holdings, Inc., a Delaware corporation AMG Service Corp., a Delaware corporation AMG Finance Trust, a Massachusetts business trust (through AMG Service Corp.) The Burridge Group Inc., an Illinois corporation Essex Investment Management Company, Inc., a Massachusetts corporation First Quadrant Corp., a New Jersey corporation (through First Quadrant Holdings, Inc.) First Quadrant Holdings, Inc., a Delaware corporation GeoCapital Corporation, a Delaware corporation J M H Management Corporation, a Delaware corporation Suite 3000 Holdings, Inc., a Delaware corporation ENTITIES IN WHICH THE REGISTRANT HAS A MAJORITY INTEREST (DIRECT AND INDIRECT) Essex Investment Management Company, LLC, a Delaware limited liability company (through Essex Investment Management Company, Inc.) First Quadrant, L.P., a Delaware limited partnership (through First Quadrant Corp.) First Quadrant U.K., L.P., a Delaware limited partnership (through First Quadrant Corp.) First Quadrant Limited, a U.K. corporation (through First Quadrant U.K., L.P.) GeoCapital, LLC, a Delaware limited liability company (through GeoCapital Corporation) Gofen and Glossberg, L.L.C., a Delaware limited liability company J.M. Hartwell Limited Partnership, a Delaware limited partnership Renaissance Investment Management, a Delaware partnership Skyline Asset Management, L.P., a Delaware limited partnership Systematic Financial Management, L.P., a Delaware limited partnership The Burridge Group LLC, a Delaware limited liability company (through The Burridge Group Inc.) Tweedy, Browne Company LLC, a Delaware limited liability company ENTITIES IN WHICH THE REGISTRANT HAS A MINORITY INTEREST Paradigm Asset Management Company, L.L.C., a Delaware limited liability company