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) have popped by as much as 16% after another analyst upgraded the stock while talk also circulates that Leap may purchase assets from larger rival AT&T (NYSE: T).

So what: RBC Capital has upped Leap to outperform from sector perform, while also bumping its price target from $9 to $11. RBC analyst Jonathan Atkin cited numerous reasons for the upgrade, including rising average revenue per user due to its Muve music service, as well as seasonal strength and stabilizing competitive pressure.

Now what: Atkin also increased his fourth-quarter customer addition estimates from 700,000 to 764,000 and net adds from 25,000 to 130,000. He notes that Leap offers a better smartphone experience than prepaid competitor MetroPCS (NYSE: PCS), and the move follows up another analyst upgrade just two days ago that caused a jump of its own. AT&T may need to divest some of its assets in the hopes of winning regulatory approval for its proposed purchase of T-Mobile, and the potential deal with Leap could make Leap the fourth-largest wireless carrier.

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Fool contributor Evan Niu owns shares of AT&T, but he holds no other position in any company mentioned. Click here to see his holdings and a short bio. 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 has a disclosure policy.