Orchard Street Investment Management LLP has confirmed the deal with insurance broker Marsh to take nearly 40,000 sq ft at Belvedere.
The 104,000 sq ft Grade A development on Booth Street in Manchester city centre was completed in the first quarter of 2009 and now has only 23,000 sq ft left to let.
Marsh, part of the global MMC Group, will occupy 39,482 sq ft over the second, third and seventh floor of the landmark building on a 10-year lease.
The move will allow Marsh and sister company Mercer to consolidate offices currently in Clarence Street, Booth Street and City Road East to Belvedere. The move is expected to be completed in early 2011.
The deal follows that with CB Richard Ellis to take 8,105 sq ft. Belvedere is already home to Towers Watson, Steelcase, Altium and Arrow Global.
Andrew Jenkins of Orchard Street said: "We are delighted that a world class occupier such as Marsh has chosen Belvedere as its new Manchester base. We have worked closely with our appointed letting agents to ensure that we can accommodate a variety of requirements and are confident that the remaining space will soon be occupied."
Alex Russell of joint letting agents, WHR Property Consultants, adds: "Belvedere has been the success story of 2010 so far and interest in the remaining space is high."
Jones Lang LaSalle acted on behalf of Marsh. JLL also represents Orchard alongside WHR.