Knightsbridge Estate has purchased the Southampton city centre property.
The vendor was Helical Bar and the sale price was in the region of £3.5m.
Cumberland House is a 30,755 sq ft office building and is currently let to Coffin Mew and Lucite International, which is a member of Mitsubishi Corporation.
There is currently 24,000 sq ft of office space still available to let.
The letting agents at Cumberland House are JLL and Realest.