“These mansion-size apartments with 30-mile views will go unoccupied much or most of the time. These towers are shaped by their clientele: a transnational nouveau riche looking for a second (or third or fourth) home. Having made fortunes in nations less regulated economically and less stable politically than the USA, these buyers want a safe investment as much as, or more than, shelter. Could this boom be a bubble? Richard Wallgren, 432 Park’s marketing director, says that it’s hard to overbuild in Manhattan. One57 says that more than half of its buyers come from outside the USA, including 15% from China. One57 will receive tens of millions in tax breaks to encourage construction.”
http://www.usatoday.com/story/news/nation/2013/12/12/new-york-high-rise-boom/4005289/