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 life settlements specialist Life Partners Holdings (Nasdaq: LPHI) plummeted as much as 19% in intraday trading on heavier-than-average volume.

So what: A good way to shake up your investors is to confirm reports that your company is under investigation by the Securities and Exchange Commission. And that's exactly what Life Partners did today. Since late last year, The Wall Street Journal has been questioning the claims Life Partners makes about the life expectancies of the holders of the policies it sells. This is a key point because longer-than-expected life expectancies mean lower-than-advertised returns for investors in those policies. The company's press release was short on details about the investigation, but it followed an article from The Wall Street Journal that revealed the investigation and confirmed that it involves the life expectancy estimates.

Now what: Figuring out the outcome of the investigation is largely a guessing game at this point. A bad outcome could mean the company would have to deal with fines and other actions, not to mention the fact that revised life expectancies, and therefore returns expectations, could make it tougher to attract policy buyers. However, market sentiment also often overshoots the mark in cases like this, so investors may want to watch for opportunities to buy the stock if concerns cause it to sell off beyond a reasonable point.

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Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his Motley Fool CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool's disclosure policy prefers dividends over a sharp stick in the eye.