A California real estate investment firm has purchased the IBM Corp. campus in Rochester and plans to add more tenants and uses to one of the largest commercial sites in Minnesota.

Los Angeles-based Industrial Realty Group LLC said it bought the 500-acre complex with plans to create "a dynamic, mixed-use, multitenant campus, which will bring businesses and job opportunities to Rochester." IBM will remain on a portion of it.

"The campus employed thousands of innovative people over the years," John Mase, chief executive of IRG said via e-mail. "We hope to continue that legacy. Rochester has an excellent workforce. The property also has desirable, quality office and industrial space, offering companies flexibility to meet their current needs and expand in the future. We have already talked to a variety of interested tenants and we are confident there will be high lease activity to come on the campus."

The campus is made up of 34 office, manufacturing and warehouse buildings that contain more than 3.1 million square feet on a prominent site along Hwy. 52.

IBM will lease eight of the buildings on the east side of the campus near the highway. But the broader campus will get a new name, an IRG spokeswoman said.

IRG didn't provide a purchase price and a state record of the sale wasn't available as of Tuesday afternoon. The sale closed Friday.

IBM first started to operate in Rochester in 1956. The facility, which became the home of IBM's minicomputer development and manufacturing, grew to be IBM's largest under one roof.

Rochester was the development and manufacturing site for IBM's midrange computers, a business that peaked in the 1990s when the company had 8,100 employees at the site. As those machines were supplanted in businesses by personal computer-based servers and networks, the company scaled back its presence in Rochester. Today, it employs about 2,700, according to federal safety data cited by the Rochester Post-Bulletin.

IRG operates a portfolio of more than 100 million square feet of space in 28 states and has a history of redeveloping large corporate campuses, such as McClellan Park in Sacramento, Calif., which consisted of a runway and supporting aviation facilities and the former Maytag plant and offices in Newton, Iowa.

One of the company's more recent projects is the Goodyear Tire and Rubber Co. headquarters in Akron, Ohio, that included the construction of a new headquarters and conversion of an old factory into retail, residential and hotel space.

Twitter: @nicolenorfleet