Northern Rock's vacant Wearside office complex has been finally sold – bringing 900 jobs to the city.
Electricity and gas supplier npower is transferring staff from its offices in Newcastle city centre after snapping up more than 200,000sq ft of office space at Rainton Bridge.
The building was originally built as a new home for up to 2,500 Northern Rock staff, but plans were abandoned when the bank ran into trouble 18 months ago.
The building has been complete for some time and there were rumours City of Sunderland College might take it over.
Now npower has announced it has bought the building in a multimillion-pound deal to rehouse staff based at Carliol House in Newcastle, where the lease expires next year.
The teams to be based at Rainton Bridge will handle the setting up new customer registration, billing and collections, as well as operational support.
The Echo understands there are no immediate plans to take on more staff, but the new premises give npower plenty of room to expand.
Julie Jaglowski, npower's Director of Residential Customer Services said: "Our aim was to find the right location, building design, use of space and working environment to enable our staff to deliver outstanding customer service.
"This new site will become the template for all future npower developments."
Sunderland Council leader, Coun Paul Watson said: "We're delighted that npower has chosen Sunderland for the site of its new regional headquarters.
"The purchase of this building is one of the largest property deals to take place in the UK in the last 18 months and the city council is pleased to have played a major role in making this happen.
"The city has a huge amount to offer businesses of all sizes and the growth of many headquarter operations here is testament to that."
Rob Laddle, npower Head of Property and Workplace Resources, said: "Creating the right environment for our staff to deliver outstanding customer service is important to us so this is brilliant news for our business and our people."