A partnership between affiliates of Boston-based Rockpoint Group LLC and New York-based Fisher Bros. has acquired interest in two Manhattan office buildings from National Bulk Carriers Inc., a New York-based real estate investment company originally owned by the late Daniel K. Ludwig. 

The partnership will receive approximately 50 percent interest in the buildings at 1345 Avenue of the Americas and 605 Third Ave. in Manhattan. Combined, the properties contain approximately three million square feet of space.

Affiliates of Fisher Bros. already hold the remaining 50 percent stake in both buildings, and Fisher Bros. continues to manage the properties.