ISG has occupied 10,845 sq ft on the fifth floor of Building 1 at Exchange Quay in Salford Quays.
The UK provider of new build, refurbishment, fit out and project management services has taken a ten-year lease with an option to break at year five.
ISG is joined by Dun & Bradstreet, which is taking the 3,080 sq ft Suite 5.3, Building 8, on the fifth floor on a five year lease.
Property and construction consultancy, RLB Rider Levett Bucknall, is taking 4,846 sq ft Suite 5.2, in Building 8 on a ten-year lease with a break option at year five.
Bluesky Travel Systems has also increased its space at Exchange Quay by taking an adjoining suite of 4,041 sq ft on the seventh floor of Building 8, bringing its total occupancy to 12,132 sq ft.
Craig Tatton, managing director of ISG's regional business, said: "Taking space at Exchange Quay has enabled the business to bring together a number of office locations within Manchester across a single floor of this prestigious building, whilst providing additional capacity to support future expansion."
David Clark, head of commercial at Exchange Quay Management, added: "2008 has been extremely positive for Exchange Quay and these lettings, all completed at headline rents of £17.50/sq ft, certainly rounds off the year nicely."
DTZ & Canning O'Neill acted for the landlord, Exchange Quay Master Trust, while P3 advised ISG, and CBRE acted on behalf of Dun & Bradstreet.