The firm been appointed as lead contractor on a third Nordic data centre project, also for a global technology company, worth £120m.
The first project was fully handed-over in February, and the second will be completed over the summer.
ISG has also secured a £20m upgrade of two existing data centres for a global banking and financial services organisation in the UK.
David Lawther, ISG chief executive officer, said: “We are delighted to continue to be a key data centre delivery partner, as we grow both in scale and resource to service this highly specialised sector.”