Liberty Property Trust today announced that it will develop a 140,000 SF, 2-story office building for Aetna Insurance on 12 acres of land at Liberty Cotton Center Business Park.

“Aetna is a valued national Liberty customer and we are pleased to have the opportunity to work together in Arizona,” said John DiVall, senior vice president and city manager for Liberty’s Arizona region. “Liberty Cotton Center remains a highly desirable location for companies doing business in the market. The Aetna project will be our fourth development in the park. It’s been very exciting to watch Cotton Center really fill out and take shape as a major employment center in the area.”

Aetna has signed a long-term lease for the building. Liberty will break ground on the sustainable Class A building – which has been designed to achieve LEED certification – in early August and expects to deliver it in June 2013.

“Phoenix is an attractive place to do business, the center of a dynamic regional economy,” said Tom Kelly, president of Aetna Medicaid.   “We like the Cotton Center location, and the LEED certification is a strong enhancement.  Aetna has a long commitment to sustainability efforts, and the green building design aligns with that broader strategy.”

The building has been designed by Balmer Architectural Group. Wespac Construction will serve as general contractor. Both companies are based in Phoenix. Aetna was represented by Jones Lang LaSalle’s national Corporate Solutions Team, with local representation by John Pierson. Liberty Property Trust was represented by Mark Detmer, Bo Mills, Jackie Orcutt, Karsten Peterson and Dave Seeger of Cushman and Wakefield.

Liberty purchased Cotton Center in 2007 in a deal that included nine buildings and 38 acres of land. The company has developed four buildings in the park, including the one announced today. The master plan includes the potential for one more 100,000 SF building on the remaining seven acres of land.

With the completion of the Aetna building, Liberty Cotton Center Business Park, which is currently 97.5% leased, will offer more than 1.225 MSF of Class A office and flex space. The park is located within the 280-acre master planned Cotton Center business community, five minutes from Sky Harbor International Airport, in the heart of metropolitan Phoenix.

Other key tenants include Freeport McMoran, Caris Diagnostics, Education Management, United Health Care, GE Medical, and Progressive Insurance.

Liberty owns 1.9 MSF of industrial and office space in Arizona. In addition to Liberty Cotton Center, major holdings include Liberty 303 Business Park in Goodyear, the LEED Gold 8501 E. Raintree Drive in Scottsdale and Liberty Tolleson Center.