Denis O'Brien's engineering company Actavo, formerly called SiteServ, has expanded into the United States.
The Irish firm has bought a key division of Atlantic Engineering Group for an undisclosed price.
The deal gives Actavo operations in the US states of Georgia, Texas, Missouri, and Colorado.
The US division acquired by Actavo has 120 staff.
The Irish company already has operations in the UK, Ireland, the Caribbean and Kazakhstan.
SiteServ was sold to an O'Brien-controlled company, Millington, by State-owned IBRC at a loss of €105m in 2012.
The deal attracted significant controversy and is being examined by Commission of Investigation into IBRC along with a series of other loan sales.
A subsidiary of SiteServ won a contract to install Irish Water meters.
Welcoming the announcement, Chairman and CEO of Actavo Sean Corkery said: "The US is an important, dynamic market for us - we see strong demand in North America for the telecommunications solutions we can now offer.
"This is a logical next step for us at this time and takes Actavo into new areas, both geographically and in terms of our customer proposition," he added.
Actavo has operations in over 100 locations internationally, with a global workforce of 5,000 providing network, in-home, industrial, hire and sales, building and event solutions to companies.