Wall Street may have had a roller-coaster third quarter, but the New York City housing market kept running smoothly. Two reports released Tuesday show that the Manhattan real estate market continues to perform significantly better than the rest of the nation. That said, market watchers warned that tough times for big Wall Street players could slow down the city's sales boom. In the third quarter, Manhattan residential real estate sales increased 65.6% from a year ago, according to a report from Prudential Douglas Elliman. The number of condo and co-op units on the market fell 31.7% from the prior year. Despite the big drop in available homes, prices remained relatively stable. The median sales price for a condo or co-op increased 2.3% to $864,397, the report said. A report from the Corcoran Group, meanwhile, said sales in the quarter rose 20% from a year ago, while the average sales price increased 5%. Although the two reports are supposed to track the same sales in the market, discrepancies are often the norm because of sampling issues. Nonetheless, the data paint the New York City market in a much better light than the rest of the country, where prices are flat to falling, sales are down and inventories have reached historic highs. The S&P Case-Shiller Index released last week showed home prices fell 3.9% in July from a year ago in the 20 largest U.S. cities.