"SiriusXM has grown from a pioneering start-up to a media powerhouse in less than 15 years of service by providing listeners with the best audio entertainment available," said CEO Jim Meyer. "Our exclusive, unmatched content and ease of use has led us to this important subscriber milestone."
Stern and SiriusXM late last year extended their partnership for several years. The satellite radio firm also offers such major sports as NFL football, NBA basketball and MLB baseball, among other content.
Meyer added: "We believe there is more success to come because of our relentless search for new and exciting content, our intense focus on subscriber satisfaction, and our significant investments in next-generation services and platforms."
SiriusXM plans to report full first-quarter results on April 28. For 2015, it had posted its strongest full-year subscriber growth since 2007.
Liberty Media currently owns a stake of about 62 percent in SiriusXM. Liberty CEO Greg Maffei earlier this year was asked about the company's longer-term plans for its stake. "Time is on our side," he said. "I believe we're likely to be the 100 percent owners at some reasonable price."
Later on Monday, Liberty shareholders will vote on the proposed creation of three stocks to track different businesses it owns: SiriusXM, the Atlanta Braves and its other assets.
This article was first published by The Hollywood Reporter.