NEW YORK CITY—While the performance of the Manhattan commercial real estate market last year—and expected market conditions for 2016—appear strong at first glance, numerous signs of a shift in the cycle have emerged.

In its press briefing on the fourth quarter, held Tuesday in Midtown, Cushman & Wakefield provided a largely upbeat report but its data was peppered with notable dips in 2015 and uncertainty for what lies ahead.

New leasing activity across Manhattan last year came to 28.2 million, among the third highest levels in a decade, but it fell by 14% from 2014. This year, "office leasing will experience either moderate growth or a moderate slowdown," says Gus Field, vice chairman. "We're at the five-year mark of the expansion cycle, and that's where previous such cycles ended."

Still, Manhattan's three major markets closed the year with vacancy rates in the single digits. Midtown South posted a 6.2% rate while Midtown slipped to 8.8%, a 1% year-over-year decrease and Downtown finished 2015 at 9.4%, a slight .3% year-over-year decline.

At year-end, the overall average asking rent in Manhattan increased 5.7% year-over-year to $71.58 per square foot from $67.70 per square foot. Overall absorption for the year was positive in all three major markets, totaling nearly 4.5 million square feet.

Meanwhile, the investment sales market appears to present question marks, according to Robert Knakal, chairman, New York investment sales. "While 2015 was a great year, cap rates have gone up for the last two quarters, so that's created some concern."

Further, he noted, "for the last two to three months, we've seen resistance in the land market. Sites that expected sale prices of $750 to $800 per square foot are getting bid at $600 to $625 per square foot. Land and hotels are the first shoes to drop in a correction. We believe that the dollar volume of sales in 2016 will be significantly lower than it was last year."

On the retail front, the impact of ecommerce remains an open question, added Joanne Podell, vice chairman. "It's not an ecommerce versus brick-and-mortar approach, both have to work together. Those retailers who embrace the omni-channel experience will succeed."

Manhattan average retail ground floor asking rents increased in five of the 11 retail corridors, with the Flatiron district seeing an increase of 6.9%, the Meatpacking district realizing a 5.2% increase, SoHo pulled in a 4.6% increase while Lower Manhattan rents rose 4.2%. The availability rate increased in eight of the corridors, with Herald Square/West 34^th Street closing the year up 8.3% and Fifth Avenue from 42nd to 49th St. up 6.2%.

In the equity and debt market, CMBS persevered in 2015 despite global economic issues creating volatility in fixed income markets, noted Steve Kohn, president, equity, debt & structured finance.

Looking forward, he questioned if this is a period of "short term volatility or a longer term upward trend in capital costs."

Kohn also predicted a fall off in apartment development as financing has become increasingly difficult to secure. "Lenders are getting more conservative and construction is getting tougher to finance, especially condominiums. It's not quite as tough for rentals but the market is getting tighter every day."