Unico Properties LLC, a Seattle-based real estate investment company, announced this afternoon that a joint venture in which it’s involved has bought the Rock Pointe Corporate Center, on downtown Spokane’s periphery.

The 11-acre Rock Pointe campus, located at the northeast corner of Boone Avenue and Washington Street, consists of four office buildings with a total of nearly 559,000 square feet of floor space. Unico said in a press release that it plans to make significant upgrades to the buildings to “return the entire portfolio to Class-A status.”

Rock Pointe currently is 86 percent occupied, and its tenants included Pitney Bowes, the Washington state Department of Social and Health Services, Verizon, and energy-management company Ecova Inc., the Avista subsidiary that’s in the process of being sold.

With the purchase, Unico’s Spokane portfolio now includes a total of about 890,000 square feet of floor space. The company also owns and manages the Bank of America Financial Center, downtown Spokane’s tallest building, which it bought in 2007.