Mountain Development Corp. has sold a state-of-the-art data center it recently completed in Clifton for $53.9 million to the California Public Employees’ Retirement System and the private-equity firm GI Partners.

The sale of the 215,000-square-foot center, named NJR3, closed earlier this month, according to CoStar, which tracks commercial real estate data. The purchase price translates to $251 a square foot. Mountain Development, based in Woodland Park, opened the facility at 2 Peekay Drive in June.

Telx, a Manhattan-based provider of data center and interconnection services, is the long-term tenant and operator of the data center and will continue as both. It has 15 to 20 employees at NJR3.

CalPERS is the largest U.S. pension fund, and GI Partners is a middle-market private equity firm based in Menlo Park, Calif.

“It’s really just a change-out of the people that own the bricks and mortar,” Mountain Development President Michael Seeve said on Wednesday.

Mountain Development is “delighted” to sell the data center to “really well-regarded” institutional investors,” Seeve said. He described Telx as one of the most expansive companies in the state, in terms of growing its footprint.

The 2 Peekay Drive data center is Telx’s flagship facility.

“For Telx, this represents a financial transaction and in no way changes the operational aspects of NJR3 or any operations taking place on the Telx Clifton campus,” Ron Sterbenz, Telx senior vice president for product and marketing, said in a statement. “This is a financial decision that allows each party to focus on what we do well, and for Telx, that is operating both data centers and its encompassing campus.”

Telx previously said it planned to use the building, its campus and an adjacent facility it owns at 100 Delawanna Ave. to create a future-technology incubator for data centers.

Sterbenz said Telx still owns the 100 Delawanna building “and although GI Partners’ investment vehicle is 2 Peekay’s owner and landlord, Telx is the exclusive tenant and in complete control of the day-to-day operations of the building.”