Security specialist ADT has completed a deal to take three floors at Bruntwood's 1 New York Street in Manchester city centre.
ADT will occupy the first, second and fourth floors when it moves in before the end of the year.
There is now 36,000 sq ft remaining to let at the 107,000 sq ft building, which completed one year ago.
Andrew Butterworth, director of Bruntwood, said: "Since the 1 New York Street scheme completed in October 2009, we have attracted seven new customers totaling approximately 70,000 sq ft. We are delighted with the development's success, which is a reflection of the building's quality, the environment we have created on New York Street and our customer focused approach to business."
DTZ and WHR are joint letting agents on the building.