US developer Tishman Speyer has put its Openturm office tower in Frankfurt back on the market after a failed attempt to sell the trophy building to KanAm in 2008. A Tishman Speyer spokesperson confirmed to PropertyEU that the US developer and investor has mandated CB Richard Ellis, BNP Paribas and UBS investment bank to market the building, which is worth between EUR 500-600 mln.