According to a study done by PricewaterhouseCoopers, Prague is one of the cities in which it is most favourable to buy office space (the other cities include Helsinki, Warsaw and Budapest). PWC claims that Prague is one of the most highly demanded locations, but however sees a risk of the yield gap between western prime locations being closed too fast. Note that OPG rents offices in Prague where occupancy rates reached 90% by the end of 2004 and recently acquired an office building in Warsaw.