PROVIDENCE — Blue Cross & Blue Shield of Rhode Island has sold the two downtown buildings it owns to a Boston real-estate investment firm, both companies announced yesterday.

Berkeley Investments closed on the deal April 30, according to Blue Cross spokesman Chris Medici. The sale price was not disclosed. In January, a Blue Cross spokeswoman predicted the company could garner $20 million from the sale.

Blue Cross is building a 13-story headquarters near Waterplace Park, also downtown, which it hopes to move into late next year or early in 2010. Until then, Blue Cross will lease the two buildings it sold to Berkeley, along with three other facilities it has been renting in Providence.

“We’re very pleased with the arrangement with Berkeley Investments,” Medici said. “It looks like they’re committed to downtown Providence, which is a good thing for the city. It’s very nice to see someone from outside the city make a long-term commitment to the city.”

Berkeley, which buys, develops and manages buildings for research and development, office and industrial uses, said in a statement it plans capital improvements on both buildings.

“The location of the buildings near I-95 and lack of available large blocks of space in downtown Providence will benefit Berkeley as we reposition the assets and begin marketing space to tenants,” Berkeley vice president Steven R. Brooks said in a statement yesterday.

The buildings are 15 La Salle Square, across the street from the Dunkin’ Donuts Center, and 1 Empire St., near Trinity Repertory Company. Both buildings are six stories. The La Salle Square facility contains 138,128 square feet of office space; the other has 99,648.

Blue Cross’s new headquarters will stand 237 feet high and have 325,000 square feet of space. In January, the cost of the project was estimated at $114 million. It is being built above the parking garage for two residential towers being constructed next to Waterplace. Blue Cross would have rights to 180 spaces in the garage. The new building will have some retail on the first floor.

pparker@projo.com