The market didn't exactly jump for joy with Sirius XM Holdings (SIRI -0.85%) following its first-quarter results on Wednesday. Revenue rose 6.3% to hit $1.375 billion, in line with analyst expectations but the satellite radio provider's weakest top-line growth since 2011. Free cash flow, operating cash flow, and earnings grew even faster, up 31%, 34%, and 40%, respectively. Sirius XM's profit of $0.06 a share did beat Wall Street's bottom-line target.  

The stock opened slightly higher, but it would go on to meander through most of the trading day -- closing 0.3% lower on the day. Decelerating growth can cool off investors, but the biggest thing holding Sirius XM back on Wednesday is that it didn't boost the seemingly conservative full-year guidance it issued earlier this year. In short, it stuck to its goal of 5% revenue growth for all of 2018 -- its weakest top-line showing as a public company -- with free cash flow and operating cash flow faring even worse despite the hot start to the year.

Katy Perry wearing headphones at a Sirius XM interview.

Image source: Sirius XM Holdings.

Turning up the dial

Slowing growth hasn't been a deal breaker for the stock. Sirius XM stock, which has climbed for nine years in a row, is still trading 17% higher so far in 2018, on pace to stretch one of the market's biggest winning streaks. There's a good chance it will extend that streak to 10 years, but it won't be easy.

Bears have started to move on. Sirius XM short interest is at a 52-week low. The boo-birds clearing out may seem like a positive development -- validating the business -- but it also decreases the likelihood of a short squeeze driving the shares higher when good news breaks.

Fortunately for investors, satellite radio is showing no signs of peaking, and Sirius XM remains the only game in town. Growth may be slowing, but with 33.1 million total subscribers on its rolls after adding another 330,000 accounts through the first three months of this year, Sirius XM may just be scratching the surface on what it can make off its well-heeled clientele. 

Throw in Sirius XM's penchant for buybacks as it improves its profits on a per-share basis by eating away at its gargantuan share count and you have a recipe for success here. It's unfortunate that it didn't lift any aspects of its guidance higher on Wednesday. Sirius XM has historically put out a weak outlook that it nudges higher with every passing quarter. It will be problematic if the trend continues, but for now, it's hard to bet against momentum.