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 prepaid wireless carrier Leap Wireless (Nasdaq: LEAP) are getting disconnected today, down by as much as 10% after the company was downgraded by Jefferies.

So what: Jefferies cut the stock's rating from buy to hold, while also lowering its price target from $12 to $10. The sell-off is a knee-jerk reaction to the negativity, despite the fact that even a $10 price target is higher than yesterday's close of $9.25, and much higher than the low of $8.31 seen so far today.

Now what: Leap markets its prepaid services under the Cricket brand, and Jefferies cites added risks on the horizon as larger carriers start to focus more on the prepaid segment. In related news, Jefferies upgraded Verizon (NYSE: VZ) from hold to buy while also boosting its price target on that stock from $33 to $45. Fellow prepaid carrier MetroPCS (NYSE: PCS) also felt some wrath as Jefferies knocked its price target from $15 to $12, although it was able to keep its buy rating.

Interested in more info on Leap Wireless? Add it to your watchlist by clicking here.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.