NME Radio stopped broadcasting at midday on Monday, shortly before NME magazine owners IPC Media announced a decision to bring the station back in-house.
The award-winning station was taken off air without warning, with current operator Town & Country Broadcasting saying its broadcasting licence would be returned to Ofcom, and that its branding licence with IPC had been terminated with immediate effect.
NME Radio presenter Michelle Owen confirmed the decision on Twitter, saying: "To those asking, it's with sadness I inform you NME Radio is no longer on air.
"A massive thanks to the bands and artists who did sessions and chatted, thanks to you for listening to new and real music."
Industry news website RadioToday.co.uk reported that the station's Facebook page, website and Twitter feed were also immediately taken offline.
In a statement Martin Mumford, managing director of Town & Country Broadcasting, said "NME Radio isn’t part of Town and Country’s core media business in Wales," and that the company had decided to concentrate on other local stations.
But IPC told Press Gazette it had actively taken the decision to return the radio station to its control, and that it would announce plans for a relaunch later this month.
A spokesman for IPC said: “After almost three years of working with Town & Country Broadcasting on NME Radio we have decided to terminate the arrangement in order to focus our attention on developing new ways in which NME’s audience can engage with audio content… we look forward to unveiling exciting plans in the coming weeks."
NME Radio was launched in 2008 by XFM's Sammy Jacob, and broadcast nationally on DAB, Sky, Freesat and Virgin Media platforms, along with occasional FM radio slots, until 2010, when Jacob's DX Media ended its licensing agreement with IPC.
Later that year Town & Country Broadcasting purchased the licence from IPC and relaunched the station on some regional DAB networks, along with Freesat and Sky.
Since the end of 2011 it had been broadcast through the NME website, iPhone app and across a limited number of regional DAB networks.
On Tuesday IPC media announced the appointment of former NME section editor and BBC Radio One music reporter Greg Cochrane as the new editor of NME.com. Cochrane will replace Luke Lewis, who recently left to become editor of the newly launched BuzzFeed UK.