The marble lobby at CitySpire, a skyscraping 72-story tower in Midtown, bustles with rushing people bundled against the cold. Nattily dressed doormen hail taxis and see to a constant stream of deliveries.
Yet the mixed-use building — the first 23 stories house offices — is not as crowded as it appears. CitySpire, at 150 West 56th Street across from Carnegie Hall, is one of the least occupied buildings in Manhattan
, with more than 60 percent of its residential floors made up of investment properties and pieds-à-terre, according to data from the New York City Independent Budget Office.