Sirius XM Radio (Nasdaq: SIRI) shares hit another two-year high today, after the satellite-radio provider showed hearty third-quarter metrics and announced a savvy debt move.

For the fifth consecutive quarter, Sirius XM is reaching out to a larger audience. The media giant added 334,727 more accounts than it shed during the past three months, closing out September with nearly 19.9 million subscribers.

Churn and free trial conversions continue to trend favorably on a year-over-year basis. On a sequential basis, churn slipped slightly, though more and more drivers are choosing to convert into self-paying customers after their free trial offers expire.

Between the two services, XM remains the larger player. XM's 10.2 million subscribers top the 9.6 million at Sirius -- but the gap continues to close. As long as Sirius doesn't lose Howard Stern in December, Sirius should overtake XM at some point next year.

It's not as if that really matters now that the two companies are one. However, since the satellite radio heavyweight offers "best of" packages at a premium to the other service's subscribers, it's good business to see both XM and Sirius drawing crowds.

Sirius XM also announced that it plans to offer $550 million in new senior notes that will mature in 2018, primarily to buy back its 2013 debt. It's a great move. Sirius XM should be pushing out a repayment event five years into the future, and it will hopefully come at a cheaper financing rate than the 11.25% senior secured notes due in three years.

There aren't too many flaws in Sirius XM's strategy these days. Cynics who feel that Pandora streaming through the growing number of Apple (Nasdaq: AAPL), Research In Motion (Nasdaq: RIMM), and Google (Nasdaq: GOOG) Android smartphones will eat into its growth, need a new thesis. There are tens of millions more iPhone, BlackBerry, and Android phones in the market than there were five quarters ago, so how has Sirius XM gained nearly 1.5 million more subscribers than it has lost in that time?

If you've got an answer, the comment box below would love to hear it.

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Longtime Fool contributor Rick Munarriz is a subscriber to both Sirius and XM. He does not own shares in any of the companies in this story. He is also a member of the Rule Breakers analytical team, seeking out the next great growth stock early in its defiance. The Fool has a disclosure policy.