Things never get dull for the country's lone satellite-radio provider. Shares of Sirius XM Radio (NASDAQ:SIRI) moved lower on the week, inching up 0.6% to close at $3.34. The move was in line with the Nasdaq's 0.2% dip. 

There was more going on beyond the share-price gyrations, though. Short interest on Sirius XM ballooned up to a 10-month high. On the streaming front, (NASDAQ:AMZN) finally introduced its potentially game-changing streaming music service.

Let's take a closer look.

Short people
Nasdaq publishes short interest twice a month, and its latest report was a doozy. The exchange revealed that a whopping 307.9 million shares were sold short as of the end of May. That's a dramatic spike from the 197.1 million shares shorted as of mid-May. 

You have to go all the way back to July of last year to find the last time Sirius XM had short interest this high. That's not a bad thing for those long the stock. It provides ammo for a short squeeze rally if Sirius XM delivers positive developments in the future. We'll have to wait another two weeks to see if the spike was just a fluke or part of an ongoing trend.

Prime time
Amazon's entry intro streaming music was rumored for months, and it became official on Thursday with the official unveiling of Prime Music. This is an important arrival for a few big reasons, but the thing working most in its favor is that it's an ad-free platform being made available to Amazon Prime members at no additional cost. 

Commercial-free tunes are Sirius XM's selling point over terrestrial radio, and they're also the incentive that streaming services use to snag premium signups. However, with at least 20 million Amazon Prime members out there, we now have a lot of people with streaming access to a lot of music without having an incremental cost. 

This would be problematic if it wasn't for its limitations. Not every major label is on board with the new service, and those that did sign up reportedly aren't making their newest releases available. Why give something away in a smorgasbord when there are download sales to score? This is still a potentially dangerous platform. Amazon claims to have more than a million tracks available, and a personal search found more than 1.2 million tunes on Prime Music. There are also dozens of playlists for those who prefer the traditional radio experience.

The only real surprise is that Amazon didn't wait until June 18 to introduce this service as part of its unveiling for its new device with an advanced display. Either way, tech giants are starting to take a big interest in digital music. It's not just the Beats acquisition. The New York Post reported this past weekend that Google (NASDAQ:GOOG) is in talks to buy Songza, offering $15 million to take out the curated streaming service with 5.5 million active users.

Are these moves turning tech giants into potential competitors for Sirius XM, or will it ultimately make Sirius XM, with its unique satellite-based platform that doesn't slurp data plan bandwidth, an appealing buyout candidate of its own? It wouldn't be a cheap purchase.