Mounting Inventory And Skittish Buyers Pushing NYC Condo Developers To Cut Deals

"It's really the consumer saying ‘this is enough," he said. "New developments showed a huge decline, falling 54% while resale condos only fell 25%."

Already steep competition could be set to steepen.

Manhattan's new condo inventory is projected to hit 7,900 next year, The Real Deal reported earlier this summer, citing data from appraisal firm Miller Samuel.

That is a significant increase on the average from the last few years -- which has sat between 3,000 and 4,000 units -- and means it would take about four-and-a-half years to sell all the units.