For the nation’s top managers, it’s deja vu all over again.

The top six managers have held on to their rankings for the last three years, and it doesn’t look like they’re letting go of those slots anytime soon. But this year’s list reflects more than just stability: The dominant trend is growth. In fact, a clear majority of the managers—34 in all—increased their portfolios, according to this year's NMHC 50 Managers, compiled by the National Multifamily Housing Council and research firm Kingsley Associates.

Charleston, S.C.–based Greystar Real Estate Partners commanded the No. 1 spot as the nation’s top manager for the fourth year in a row. And last year, a $1.5 billion deal struck with Equity Residential helped the firm to put more distance between itself and the rest of the pack.

With an approximate 8 percent increase in the last year, Greystar now oversees more than 214,000 units, and that doesn’t even include the company’s assets in Mexico, or its student housing activities in the U.K. But in the third-party management business, size certainly matters. Economies of scale are the name of the game in a sector where overhead costs continue to grow.

Becoming a national platform has afforded the company more opportunities to grow its presence in submarkets from coast to coast. The boots-on-the-ground local leadership by Greystar, coupled with its strong national support system, has positioned the company for continued expansion.

“That growth had a compounding effect,” says Bob Faith, Greystar’s founder and CEO. “As we have great clients that continue to build and give us the management of assets, that growth has continued.”

The company’s investments in people, technology, and infrastructure have a multiplier effect. The advantages of Greystar’s scale can easily be passed to its clients—­from sophisticated technology systems to the company’s buying power with vendors.

“What we’re finding is the benefits of that size are becoming a huge benefit to our clients as well,” Faith says.

But the company’s staying power is largely attributable to its dedication to all of the major markets it entered, stemming from its 2009 acquisition of Irving, Texas-based JPI’s management portfolio, which brought more than 41,000 units, 1,100 employees, and a national footprint to Greystar.

“We don’t enter and exit markets; when we come into a major market, we’re there to stay. That’s part of what allows us to attract [clients], because they know Greystar is committed,” Faith says.

And just as the company’s growth begets more portfolio growth, it also gives Greystar greater visibility to attract and retain the best and brightest.

“Having that staying power and commitment to the markets we’re in is one of the keys to getting great people, which is then key to being a great operator in these markets,” Faith says.

Spoils of Acquisitions
After closing on the Archstone deal in February of last year, Arlington, Va.–based AvalonBay communities jumped up six spots, breaking into the top 10 managers list for the first time this year at No. 8. The company had a net portfolio increase of 12,713 units last year, while its counterpart in the Archstone acquisition, Equity Residential, maintained its No. 6 ranking even though it saw a 6.7 percent portfolio decrease.

The Archstone deal increased AvalonBay’s portfolio by at least 35 percent, padding its resume since it was already in high-growth mode, driven by an increased development pipeline. The company started more than 4,900 units last year, after breaking ground on more than 3,390 units in 2012.

Part of that growth effort included the roll-out of three new brand platforms in 2012: Avalon, Eaves by Avalon, and Ava—a luxury, value, and urban brand, respectively. The platforms allow the company to penetrate new markets while increasing their share of the Class A space.

“One of the things we’ve been seeking to do for some time is to build a platform to leverage size and scale, and now there are systems in place to enable us to do that,” says Matt Birenbaum, AvalonBay’s executive vice president of corporate strategy.

With a central operations shared service center in Virginia Beach that serves a multitude of communities, AvalonBay has piggybacked off its consistency, realizing economies of scale that position it for further growth.

In terms of dollars, the Archstone deals were two of the largest in our industry’s history. But in terms of units, those transactions have to take a back seat. After its acquisition of Colonial Properties Trust, Mid-America Apartment Communities (MAA) jumped from No. 19 last year to No. 7 on this year’s managers list.

With an approximate 67 percent portfolio growth, the company now manages 82,281 units. By adding some fresh faces, MAA reorganized its property management leadership team to accommodate the new size and blend the companies’ styles. The merger also afforded MAA some of the innovative technologies Colonial used prior to being sold.

While MAA saw the largest portfolio growth of any of the top 50, Atlanta-based CFLane also experienced rapid growth following the acquisition of Lane Management by Cocke Finkelstein. The brand-new company was created as a management entity for Cocke Finkelstein in 2013, helping the firm increase its management portfolio from 8,000 units to more than 38,000, helping it break into the list, at No. 34.

Conversely, the largest decrease in units managed was seen by Hunt Cos., with a 21.4 percent drop, bringing the El Paso, Texas–based company from No. 16 down to No. 25, settling at 44,427 units. Denver-based Aimco also saw an acute drop, shedding about 11 percent of its portfolio and dropping from eighth to No. 14, while Bell Partners and Camden also lost top 10 status, with 8 percent decreases in their portfolios.

-Linsey Isaacs is an assistant editor with Multifamily Executive magazine. Follow her on twitter @LinseyI  to continue this conversation.