Thomas Properties Group and Brandywine Realty Trust have agreed to establish a partnership to own Commerce Square, located at 2001 and 2005 West Market Street in Philadelphia, Pennsylvania.

Currently owned solely by Thomas Properties Group, the twin 41-story office towers comprise 1.9 million square feet of class A office space.

Brandywine will contribute a total of USD25m of preferred equity to the partnerships that own One Commerce Square and Two Commerce Square, and will become a 25 per cent limited partner in both properties. Brandywine's preferred equity will be invested USD5m at closing with the balance invested by 31 December 2012.

The transaction is subject to customary closing conditions and both parties expect a closing in the fourth quarter of 2010.

The Brandywine capital will be invested in maintaining Commerce Square's trophy status, with renovations to the buildings' operating systems, common areas and tenant amenities. Brandywine's equity will be used in various capital projects, including upgrades that are intended to achieve LEED status for both properties.

James A. Thomas, chairman and chief executive of Thomas Properties Group, says: "This new alliance with Brandywine will bring a highly respected company with deep roots in Philadelphia into partnership with us in Commerce Square and will provide substantial capital to improve these premier properties and maintain their position among the highest quality buildings in Center City Philadelphia. Brandywine and our firm share common values and objectives and we are confident this will be a mutually beneficial partnership."

"Brandywine is delighted to be making a preferred investment into Commerce Square, one of Philadelphia's central business district trophy-class properties," says Gerard H. Sweeney, president and chief executive officer of Brandywine Realty Trust. "Our investment in this project's value-enhancement programme will be overseen by the seasoned TPG team, ensuring a continuation of this project's long, successful track record and preeminent market position."

Commerce Square is currently over 89 per cent leased and its tenants include Delaware Investments, Ernst & Young, Grant Thornton, McCormick Taylor, The Pew Charitable Trusts, PricewaterhouseCoopers, Reliance Standard Life Insurance, Stradley Ronon, TD Bank and Wolters Kluwer Health.