After an unprecedented high-rise apartment boom, Atlanta is poised for a slowdown in new projects and a return to a renters’ market.

Several trends are merging to slow both construction and rent growth.

First, construction was started on 6,500 high-rise units in Buckhead and Midtown between 2015 an 2017, according to the Reid Report, a publication that tracks apartment development across the region. That is a historic level of apartment towers in the city’s development pipeline. Another 4,500 high-rise units remain under construction, according to real estate consulting firm Haddow & Co. It’s going to take some time for those apartments to fill up.

In fact, Atlanta didn’t have a high-rise rental market until this real estate cycle. Before that, almost all new residential towers were built as condominiums.

Another reason for the projected slowdown in apartment high-rises is the cost to develop them. Construction costs have soared more than 30 percent since 2010, when the first wave of projects started to form, according to market data.

And, now rents are struggling to keep pace with those costs. In fact, for some towers that opened between 2012-2015, effective rents are down as much as 10 percent, according to Haddow & Co.

Concessions are also being closely watched. In Buckhead, landlords are offering tenants up to two months of free rent if they will sign new leases, according to the Reid Report.

The fundamentals suggest next year Buckhead and Midtown may see the fewest number of new towers start construction since 2014.

“We are expecting a dramatic decline,” said Harvey Wadsworth, a development executive with Mill Creek Residential, which has a new high-rise under construction on Peachtree Road next to ritzy mixed-use development The Shops Buckhead Atlanta.

Apartment deliveries, or new units that come onto the market, is peaking in Midtown now and peaked in Buckhead two years ago, according to Mill Creek.

It would have been difficult to keep up the pace. Consider that in 2015, Buckhead saw almost 3,000 new apartment units delivered to the market (the majority of those were high-rise). This year, deliveries are down 40 percent, says Mill Creek.

Midtown high-rise construction is peaking now. The neighborhood is expected to deliver 2,300 units in 2017, but could see that number fall to as few as 300 units in two years.

The spate of high-rise apartments over the past seven years was new for Atlanta. It was fueled by forces in the real estate industry that emerged in the wake of the Great Recession, including barriers to first-time home-buyers such as student debt, tighter mortgage requirements and a lack of affordable single-family housing supply.

Former Novare Group and Carter executive Conor McNally was in the middle of the condo boom more than a decade ago. McNally, who now is principal at Shelton McNally Real Estate Partners, isn’t buying the projected slowdown in new apartment towers quite yet, and he is joined by analysts such as Reis.

In its latest quarterly report, Reis observed, “The apartment market continues to withstand pressure from added supply. With so much construction underway, vacancy rates were thought to grow higher.”

But, “healthy job growth provided steady demand for apartments.”

McNally believes more companies moving into the urban core will continue to spur more apartment towers, but he also believes rents, at least for the moment, have peaked.

“Anyone with new towers under construction cannot reasonably expect the significant high-rise rent growth we’ve seen to continue, at least for now,” he said. “I think we are entering a period of rent stagnation.”

Asked whether Atlanta could see a renters’ market emerge, which is often marked by declining rents and bigger concessions, McNally said, “At least we are closer to one than we have been in the last several years.”

Ladson Haddow, vice president with Haddow & Co., said how the market shakes out comes down to supply and demand.

“Supply is outpacing demand, which is resulting in a competitive leasing environment,” Haddow said. “However, the urban core is experiencing superb job growth and is increasingly becoming a more desirable place to live. It is still too soon to determine how deep the demand pool is for the surge of high-rise units delivering to the market, but it does appear that we have generally reached a ceiling on how high rents can be pushed.”