This is the second expansion for Greenberg in less than a year.The company, which served as President George W. Bush'srepresentative in the 2000 Florida recount case, had expanded to78,413 sf at the 959,791 sf building in January.

Both companies have been in the building for many years, saysJeff Patterson, president and chief executive officer of PrimeGroup. He tells GlobeSt.com that the building is now 93% leased. "Ithink it's a bit of a two-tiered market in Downtown Chicago.There's a large gap between the high-quality class A buildings andthe older class B buildings, and the former enjoys a dynamic timein this market, from a landlord perspective."

Although Patterson would not discuss the companies' lease terms,asking lease rates at the 14-year-old, 51-story building start at$23 per sf. Gregory L. Gerber and Ari Klein from the John Buck Co.represented Greenberg Traurig in its transaction, while SteveSteinmeyer and Chris Kelson of Jones Lang LaSalle representedMicrosoft.