The firm, founded by James A. Thomas, relocated corporate headquarters into a full floor at the north tower of Arco Plaza at 515 S. Flower St. It is taking more space than it occupied at Wells Fargo Center because it is expanding and reeling in its building management operations to the Arco Plaza space.

Thomas says the move was important so that the new owner can determine upgrades to restore the downtown office complex to a top spot among the Downtown Los Angeles office towers. The Arco Plaza property and its twin 52-story granite-clad towers occupy an entire city block bounded by Figueroa, Flower, Fifth and Sixth streets.

Thomas Properties Group took over a full floor in the north tower at 515 South Flower St. A plan will be unveiled in the near future for improvements to public spaces and mechanical systems.

Thomas Properties Group and CalSTRS are the major investors in TPG Plaza Investments, the new entity that owns Arco Plaza. Kings Capital, a privately held company controlled by Kenneth A. Picerne and managed by the PicerneGroup of San Juan Capistrano, CA, obtained an agreement to purchase the towers from Japan-based Shuwa Investment Corp. in April 2002, and continues as a partner with Thomas Properties Group and CalSTRS.