Around 400 jobs are set to come to Birmingham after The Mailbox secured a new tenant for its revamped office space.
Advanced Computer Software Group (ACS), which currently has a base on Birmingham Science Park Aston, has agreed a pre-let deal on 45,000 sq ft of space in the mixed-use complex which has recently undergone a £50 million facelift.
It is believed to be the largest single floorpate available within Birmingham and will see ACS take the entire third floor as well as it becoming the firm's Midlands HQ.
The office accommodation is currently undergoing remodelling work to reconfigure it to grade A standard with a dedicated reception, due for completion early next year.
ACS provides a range of software and IT services to the private, public and not-for-profit sectors aimed at reducing costs, improving efficiencies and driving growth.
Headquartered in Slough in Berkshire, the business is one the UK's largest in the field and currently employs 2,000 people at various locations across the UK.
Chief executive Gordon Wilson said: "The sheer size of this accommodation gives us the ability to bring together a number of our functions under one roof and in a prestigious location.
"The combination of The Mailbox's proximity to New Street station and the city's other transport links, its unique position above the retail and leisure offerings and the quality of the refurbishment programme, were all key elements in our decision."
The Mailbox was acquired from city developers Alan Chatham and Mark Billingham in 2011 for £127 million by a joint venture between Brockton Capital and Milligan.
It has since undergone a comprehensive renovation programme including a new-look Harvey Nichols and main mall, Everyman cinema and glass roof.
Brockton partner Simon Samuels added: "This letting is a perfect example of the quality and calibre of occupier that we felt would be attracted to The Mailbox.
"I know that the whole team is looking forward to welcoming Advanced to the Mailbox and working with them on the final stages of delivery of this prestigious commercial space."
Letting agencies CBRE and GBR Phoenix Beard jointly represented The Mailbox on the deal while JLL acted for ACS.
