Manhattan real estate prices continue to rise, even as the market remains challenged by the lack of inventory, according to an industry report. The current market pace is brisk with nearly half of all sales resulting in purchase prices that were at or above the asking price. Manhattan real estate needs to be viewed as asset class, Robert Dankner, President of Prime Manhattan Residential, tells TheStreet's Jill Malandrino. As a former trader, Dankner says just like any other tradable instrument, nothing goes up forever and the same applies to New York City's residential ceiling, but for now buyers are are keeping the market exceptionally strong.