BT has acquired Belfast-based BIC Systems Group for £17 million (€25 million).
BIC Systems founder and chief executive Mr Ed Vernon is the firm's biggest shareholder and is set to reap the bulk of the purchase price. A number of its employees, who own shares through a share option scheme, will also benefit financially from the transaction.
The company provides information technology and networking services.
Mr Vernon and the management team will continue to work at BIC Systems.
Announcing the deal yesterday, BT said it would accelerate its five-year strategic programme to win market share in the IT and networking services sector.
"This is a unique opportunity for both companies," BT managing director Mr Bill Murphy said. "I believe this acquisition will create a company of incomparable experience at a time when Northern Ireland's IT future looks bright and when IT skills have never been more essential."
Mr Vernon said BT would bring superb skills and expertise to the group.
"Together we will raise the ICT [information and communications technology\] level in Northern Ireland and that can only be good for the public and private sectors."
Both brands will be retained.
BT directly employs almost 3,000 people in Northern Ireland and there are no planned job losses as a result of the acquisition. Both companies have already worked together on a number of projects for Northern Ireland customers including Enterprise Northern Ireland.
BIC Systems grew out of a small research company established in Queens University in Belfast. It is currently one of the most significant players in the IT market there.
BT said there is an opportunity to bring the teams of both companies together in the future but that both will retain their current premises.