Invesco Lt. (Amvescap PLC prior to May 2007, NYSE: IVZ) is an investment management company headquartered in Atlanta, Georgia. It is traded on both the New York Stock Exchange and on the Toronto Stock Exchange. Invesco is a constituent of the Russell 1000 Index and the Russell MidCap Index. It has branches in 20 countries, with more than half of its business in the United States. Invesco operates under the Invesco, Invesco Aim (AIM Investments prior to March, 2008), AIM Trimark, Invesco Perpetual, Atlantic Trust, WL Ross and Powershares brand names.