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 China MediaExpress (Nasdaq: CCME) jumped more than 10% today.

So what: The advertising network has been on a tear lately, posting a 121% jump in revenue and a 148% jump in earnings over the past twelve months. The stock has risen over 80% in the past month.

Now what: It's always difficult to say what's going through traders' minds when there isn't much news. One possible explanation might be that the Federal Reserve's announcement that it's beginning a second stage of quantitative easing, traders expect to see greater inflows to foreign markets such as China, and they hope to get ahead of that wave. (The Xinhua China 25 (NYSE: FXI) jumped quite a bit this afternoon.)

Still, traders seem especially keen on China MediaExpress, perhaps for its momentum; competitors AirMedia (Nasdaq: AMCN) and VisionMedia (Nasdaq: VISN) were up considerably, though not as much, while FocusMedia (Nasdaq: FMCN) was flat.

Interested in Chinese media stocks? Add them to My Watchlist:

At the time of publication, Ilan Moscovitz owned shares of FocusMedia. 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.