Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Iridium Communications (IRDM 1.88%) plunged today by as much as 11%, after the company reported earnings.

So what: Third-quarter revenue added up to $100.4 million, a little shy of analysts' best guesses. Net income was $17.8 million, or $0.23 per share, again falling short of the consensus estimate of $0.25 per share. However, Iridium lowered its total billable subscriber growth outlook.

Now what: CEO Matt Desch acknowledged the challenges that Iridium has faced so far in 2012, but is optimistic that growth will reaccelerate in 2013. Iridium affirmed its full-year outlook for total service revenue growth of roughly 6%, but had to cut its total billable subscriber growth estimate from a range of 20% to 25% to a new target of 18%. This was due to some expected machine-to-machine subscriber additions shifting from late 2012 to early 2013. CRT Capital downgraded shares as a result.

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