NEWBURYPORT — The business cards of Newburyport residents Ken Irwin and Marian Leighton Levy will still identify their holders as “Rounder Founders,” after the acquisition of the Burlington-based roots record label by the Beverly Hills-based Concord Music Group last week.

Rounder Records was purchased by Concord in a move described as “win/win/win/win” by Rounder co-founder Irwin. Both labels have catalogues of critically acclaimed, Grammy-winning artists that now form a leading independent record label in a variety of genres. Rounder, with 35 employees, celebrates its 40th anniversary this year.

The purchase price and details of the acquisition have not yet been released.

Founded in 1970 in Cambridge by university students Irwin, Leighton Levy and Bill Nowlin, the trio first sold folk music recordings and expanded into a record label with more than 3,000 master recordings.

Rounder artists include Alison Krauss, Mary Chapin Carpenter, Bela Fleck, Steve Martin, Delta Spirit, Robert Plant, Raffi and Willie Nelson. Rounder specializes in genres such as Americana, bluegrass, Cajun and zydeco. Unlike most major labels, Rounder has been a champion of niche music throughout the years, said Irwin.

Irwin, Leighton Levy and Nowlin “will remain active with the company in a creative and advisory capacity. The company’s senior management will also remain in place,” according to the press release.

Ultimately, the decision was based on Rounder and Concord’s compatible approach to signing and recording artists. The three founders had certain criteria that had to be met in order to sell the label, said Irwin.

“We wanted to find a home for our artists, we wanted to retain the Rounder label and its legacy and find a company that could appreciate what we’ve done. We wanted to find a way to keeps jobs and have security for as many members of our staff as we could, and lastly, we wanted to have some security for ourselves,” said Irwin. Both labels are distributed by Universal Music Group, which made the transition even more seamless.

“If you’re looking for one thing, it’s easy to add other criteria, but it’s harder to find a match. We are fortunate to find a company that satisfies all of those,” said Irwin.

Rounder refused Concord’s first offer to purchase the label four years ago. As the landscape changed, the offer became more inviting to Rounder’s owners.

Leighton Levy characterized the move to sell the label to Concord, a label four times the size of Rounder, as “a strength in numbers” approach during a time of uncertainty in the music industry.

“It’s been difficult for many labels,” said Irwin. The decline of music sales and the rise of illegal downloads and torrent sites have “provided a considerable amount of pressure on music labels.”

Irwin said Rounder will continue to operate in Burlington, and the lease was recently renewed for another three years.