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: AutoChina International Ltd. (Nasdaq: AUTC) dropped 10% in intraday trading today after another China-based firm announced its auditor and CFO had resigned.

So what: A CFO resignation is always disconcerting; an auditor resignation is a huge red flag. Both have just occurred at China MediaExpress Holdings (Nasdaq: CCME).

Now what: China-based stocks often trade at a discount because of concerns that financial reporting standards are not as robust as in other countries. The resignations at China MediaExpress Holdings are fueling concerns of fraudulent financials for CCME specifically and China-based firms in general. For such stocks, investors are selling first and asking questions later.

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Fool contributor Cindy Johnson does not own shares of any company named above. 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.