The building on Ormeau Road in Belfast is now home to around 50 head office employees.
Managing director of Mount Charles Cathal Geoghegan, said: “We see the investment in Annon House not only as a suitable reflection of the dynamic, creative company that Mount Charles is, but also as a serious statement of intent both to our people and to the wider economy.
“There remains massive scope for our continued expansion and diversification. Our revenues as of September 2016 totalled £31m and we have recently outlined our ambitious plans for the ‘Road to £50m’ whereby we aim to achieve revenues of that amount by 2020. We conservatively estimate that our employee figures would rise from 2,000 to more than 3,000 when we hit that target.”
Mount Charles spans catering, cleaning, vending, security and outside event food & beverage divisions.