Acquisitive CMI has double in size following the acquisition of London-based MSP BTA.
The deal was funded by Panoramic Growth Equity and boosts CMI's turnover to over £11m and staff numbers to 100.
The company operates out of bases in Belfast, London and Maidenhead.
CMI MD Ken Roulston stated: “The acquisition will create a stronger IT service provider.
"Bob Brittaine, our Chairman, Graham Stead, Client Relationship Director, Michael O’Neill, Managed Services Director, and I have over 100 combined years in the IT services sector.
"Now we have been joined by Darron Millar as Technical Solutions Director and Victoria Millar as Client Services Director, and we are excited about what the future holds.”