Things never get dull for the country's lone satellite-radio provider. Shares of Sirius XM Radio (NASDAQ:SIRI) moved marginally higher this week, closing 0.6% higher to hit $3.38. The general market moved even higher, and Sirius XM's gain lagged the Nasdaq's 1.7% pop.

There was more going on beyond the share-price gyrations, though. Sirius XM hit another five-year high. Short interest held steady during the latter half of April. And Pandora (NYSE:P) had a notable trend reversal in its latest monthly metrics report, coming at a time when Apple (NASDAQ:AAPL) is getting closer to the launch of its own streaming service.

Let's take a closer look.

Higher ground
Shares of Sirius XM have been moving higher since posting well-received first-quarter results a week earlier. When the stock hit $3.42 on Wednesday, it was the highest the stock has traded at since March, 2008.

Since the merger between Sirius and XM wasn't completed until later that summer, this is actually an all-time high for the combined company.

Short people
The only thing that could make a fresh multiyear high sweeter for Sirius XM bulls is knowing that the satellite-radio star remains the most heavily shorted stock by share volume. Fresh exchange data this week shows that there were 380.3 million shares of Sirius XM sold short as of the end of April.

Short interest in Sirius XM peaked at the end of February, when there were more than 414 million shares sold short, but there are still plenty of skeptics to shake out. Once again, Sirius XM shorts are poorer on paper this week.

Turn up the iRadio
Apple has yet to officially announce its entry into the streaming market, where Sirius XM and several others are trying to catch up to Pandora. However, third-party reports continue to say Apple will jump in sooner rather than later.

Sources are telling London's Financial Times that Apple has struck a licensing deal with Universal Music. They also claim that Apple is completing negotiations with Warner Music Group. A deal with Sony Music has been harder to come by, but Apple is unlikely to wait on a stingy Sony Music if it already has Universal aboard.

Will Apple aim for a premium on-demand Spotify model or a more accessible ad-based Pandora platform of music discovery? Who knows? This market's about to get pretty crowded.

Pandora bread
Pandora hit a new 52-week high on Thursday, but there was an interesting nugget in the dot-com darling's latest monthly update. The number of active listeners in April clocked in at 70.1 million, up 35% over the past year. Listener hours rose 24% to 1.31 billion.

Yes, that's some heady growth. Sirius XM isn't growing its audience at this rate. However, did you notice how the hours streamed grew slower than the headcount? The average Pandora listener is tuning in less, and that's the first time I've seen that happen in a long time. More often than not, Pandora reports healthier growth in its listener hours than in its listener count.

That's not a positive development, especially when Sirius XM is ramping up its Internet offerings and tech giants are closing in.

A Sirius future
It was an interesting week for Sirius XM. The new week isn't likely to be dull.