Twenty leading European property companies are joining forces in the International Sustainability Alliance (ISA), aimed at creating the world’s biggest environmental property database. Jaap Gillis, Co-Chair of ISA and Chief Operating Officer of Redevco said ISA already represents a growing proportion of Europe's commercial real estate players, operating or occupying around 150 million m[sup]2[/sup] of floor space, with a capital value in excess of EUR 150 mln.