Ashtenne Space Northwest plans to spend £5m redeveloping Mercury Court, the 190,000 sq ft former Exchange Station on Tithebarn Street in central Liverpool.
Wayne Locke, director at Ashtenne Space Northwest, said: "Ashtenne Space Northwest has owned Mercury Court for six years and the market is now right for this significant investment to bring it up to date with modern technology and facilities, embracing the building's important status in Liverpool's economic history, creating a unique office product for the city's business occupiers.
"Having seen Liverpool Vision's inspiring Strategic Investment Framework for Liverpool for the next 15 years and with the International Festival of Business coming to the city in 2014, we need a world class office destination and we believe that Exchange Station will be the place to do business."
Mayor of Liverpool, Joe Anderson, said: "This investment from Ashtenne Space Northwest is most welcome, and will bring a major boost to this historic city centre building.
"Exchange Station has long been an important landmark in this part of the city and these plans will help maximise the building's potential as a first-class business destination. I'm looking forward to work getting underway."
Max Steinberg, chief executive of Liverpool Vision, said of Exchange Station: "The fact that Ashtenne Space Northwest is investing £5m into the first phase of development at Exchange Station is excellent news for the city. As it continues on its successful journey, Liverpool is competing on a world stage and in just a few months we will see a new office destination with 21st Century business at its forefront. We are extremely pleased to see this level of development in the Central Business District and we are sure that it will continue to attract world class businesses."
Hoardings went up on site at Exchange Station this week, with construction due to start on site at the beginning of January.