How are shares of Sirius XM Radio (Nasdaq: SIRI) like a rodeo cowboy? They are both drawn to the buck.

The satellite radio giant's stock dipped below the $1 mark this morning. Believe it or not, this is the first time that has happened this month.

Every time it seems that Sirius XM has left a sub-buck price in the rearview mirror, a price on the wrong side of the decimal awaits a few highway exits later.

Fundamentally, there are no reasons to be alarmed.

  • Sirius XM posted another strong quarter last week -- and raised some components of its guidance.
  • Liberty Capital's (Nasdaq: LCAPA) earnings report this week offered no reason to worry that John Malone may unload his 40% stake in Sirius XM.
  • Ford (NYSE: F) has warned of tough year-over-year comparisons during the second half of the year for auto sales, but Sirius XM's free trial conversion rates are up and its churn is down.

In short, there aren't a lot of lights blinking amber at this point. DISH Network (Nasdaq: DISH) was slammed earlier this week after posting a year-over-year dip in subscribers, but there is a big difference between satellite television and satellite radio. DISH's weakness may signal a downturn in discretionary spending, but it's more likely the result of DIRECTV (NYSE: DTV) eating its lunch and some folks sidestepping cable and satellite television subscription entirely in favor of streaming alternatives. Sirius XM -- for now -- is the only legitimate game in town when it comes to premium radio.

Howard Stern -- Sirius XM's largest exclusive celebrity -- is still a question mark. However, the answer is coming soon. Sirius XM indicated that Stern should have an announcement before the company's third-quarter call.

So, once again, market volatility claims another buck breaker. As a high beta stock, Sirius XM will be hard-pressed to resist selling waves in other securities. The economy's iffy recovery is also going to exaggerate these moves with consumer-facing leisure companies.

If the economy holds up and Stern doesn't serve up a bombshell, it's really just a matter of time before Sirius XM lands to the left of the decimal point.

One day, it may very well be for keeps.

Is Sirius XM worth more or less than $1 a share? Share your valuation argument in the comment box below.

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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.