UTV Media has changed its name to Wireless Group after the £100 million sale of its television assets to ITV was completed.
The company - one of only three from Northern Ireland on the main London Stock Exchange - is now focused on its radio and online division.
The sale will also see around £55m returned to shareholders.
It sees a return of the Wireless Group name - a company bought by UTV Media for £100m in 2005 when it acquired a string of local stations across Britain and TalkSport.
As of Monday, the 250 staff at UTV television in the north and UTV Ireland, became employees of ITV.
ITV chief executive Adam Crozier said the company was "committed to maintaining and strengthening the news service and UTV’s wider programming output".
"We recognise the strength of UTV in Northern Ireland, UTV Live is one of the most successful – and highest rating – news programmes in the whole of ITV," he said.
“The team has done a great job in establishing UTV Ireland and shaking up the Irish market place in the process. In just over a year on air, the channel is already running second in the market in ratings terms on a regular basis. This is a significant achievement and one we look forward to building upon with the team."
Michael Wilson will continue as managing director of UTV Television.
He said UTV Ireland was reaching 2.3m people weekly and that UTV was "by far the most watched channel in Northern Ireland".
“These are significant achievements in a highly competitive market and ITV has the scale and capabilities to build upon the future potential for both UTV channels, maximising audiences across all platforms," he said.
