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 AutoChina International (Nasdaq: AUTC), the Chinese seller of commercial vehicles, fell as much as 14.2% on very light trading volume.

So what: There's no news on this company today, other China-based stocks are generally doing all right, and the order book is almost empty with bid and ask prices miles apart. Fellow Beijing-based car dealer Lentuo International is also falling today, but again on low volume and no news of note.

Now what: With so little market-moving information to go on, it's safe to call this drop an example of a Brownian walk down Wall Street. On a light-trading day like this, share prices on foreign stocks with little investor interest even in the best of times can be jumpy to say the least. If you're buying this stock on the drop, you'd better make darn sure you know what you're getting.

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

Fool contributor Anders Bylund holds no position in any of the companies discussed here. 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 is investors writing for investors.