Our real-estate market’s surprising refusal to cool down can be chalked up to a single, low-profile foreign player. The name Istithmar is still not exactly a mainstay of Manhattan conversation, but the Dubai-based firm’s purchases in the city make Trump look like an amateur apartment-flipper. In the past year alone, Istithmar, owned by the country’s royal family, set two major records in the field. It was the first to pay over $1,000 a foot for office space (on Park Avenue) as well as the first to pick up a hotel at over a million per room (W Union Square). The ease with which the firm parts with its funds has made some aristocratic jaws drop; best of all, though, Istithmar whose moves account for 12 percent of all office and hotel purchases in the city last year shows no signs of being done. They already found time to (unsuccessfully) bid on 5 Times Square, goosing up its price in the process.