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 Clearwire (Nasdaq: CLWR) slumped more than 12% in early trading on what appear to be ongoing fears that Cox Communications' retreat from plans to build a wireless network could have broad implications for the industry in general and Clearwire in particular.

So what: Cox, which had planned to go head-to-head with AT&T (NYSE: T) in major markets, now plans to sell its wireless infrastructure and partner for service. The implication? Investing in wireless costs too much and promises too little return.

Now what: Cox isn't saying that specifically, but Clearwire's ongoing quest for external financing appears shows no signs of ending soon. And while competitor LightSquared's troubling report to the Federal Communications Commission should have raised hopes for Clearwire, investors have shown little interest in the stock. I can't blame them. Why buy when company founder Craig McCaw is dumping shares? Wait for Clearwire to report material financial progress before taking another turn at this stock.

Interested in more info on Clearwire? Add it to your watchlist.

Fool contributor Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team. He didn't own shares in any of the companies mentioned in this article at the time of publication. Check out his portfolio holdings and Foolish writings, or connect with him on Twitter as @milehighfool. You can also get his insights delivered directly to your RSS reader.

Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool's disclosure policy is at least 10% better than competing disclosure policies.