They are developers, buyers, and property managers. For-profits and nonprofits. National players and regional specialists.

They are the AHF Top 50 Owners of 2014, and together they hold more than 560,000 affordable housing units across the country.

None is bigger than The Michaels Organization, by far the largest affordable housing owner in the nation. The Marlton, N.J.–based firm not only holds the No. 1 position on the owners list, with a portfolio of 46,662 units owned at the start of 2015, but it also heads the AHF Top 50 Developers of 2014, a sign of the company's overall strength in the sector.

The owners rankings are based on the number of affordable units owned as of Jan. 1, 2015, with only general-partner owners eligible. For 2014, 107 firms completed surveys to be considered for the annual list.

In addition to their numbers, the AHF 50 told us their greatest concerns for the year ahead.

"Among the biggest challenges that face the industry are escalating costs, availability of labor, finding funding sources, and ­ever-increasing consumer demand," says Michael Costa, president and CEO of Highridge Costa Cos., No. 9 on the list. And, like its peers, the firm is always working to obtain funding.

"We're striving to keep up with the need for more affordable family and seniors housing by finding creative new ways to ­finance affordable housing through effective public–private partnerships, primarily in California, Arizona, Colorado, and Texas," says Costa.

That funding applies to new-construction deals as well as existing properties. Highridge Costa is taking a close look at how to position its older properties. The firm has a growing number of communities that have met their low-income housing tax credit ­(LIHTC) delivery and ­initial 15-year compliance requirements, and therefore are ready for a transfer of ­ownership.

"Our plan here is to consolidate our business to the Western United States," Costa says. "We're doing this through a strategic business plan consisting of transferring 15-year–plus assets we own that are located east of the Rocky Mountains to third-party purchasers, while transferring those west of the Rockies to a new affordable housing partnership sponsored by Highridge Costa."

This will allow the company to keep those properties under ownership. It plans to use tax-exempt bonds and LIHTCs to finance the acquisition and rehabilitation of each purchased asset. Highridge Costa, which is also active in new development, r­ecently completed the acquisition–r­ehab of three California properties and has more in the works.

Costa isn't the only owner concerned about preserving or maintaining aging properties. Eleven percent of the companies cited it as their biggest worry, behind only the elimination of or changes to the LIHTC program and fewer local ­resources.

The AHF Top 50 Owners employ nearly 47,000 people, with 34 firms increasing their staffing in 2014. Thirteen companies maintained, and three decreased, their work­f­orce levels last year.

See the complete AHF 50 owners list.