A joint venture involving Keystone Property Group of Conshohocken and Wayne-based Argosy Real Estate Partners has sold the Devon Square office complex in Tredyffrin Township for $33.5 million, the companies said in a release this week.

The buyer of the two-building, 140,000-square-foot office property at 724-744 W. Lancaster Avenue is an affiliate of King of Prussia-based Westover Cos., according to records filed with the Chester County Recorder of Deeds. The transaction closed on April 24.

The Devon Square buildings are 95 percent occupied, with tenants including Merrill Lynch, Penn Liberty Bank, Keller Williams, and Main Line Surgery Center.

An affiliate of Keystone had acquired the property for $9.18 million in 2005, Chester County records show. Subsequent improvements to the property included interiors and exterior updates and a remodeling of the building's common areas, according to the companies' press release.