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 paper and tobacco products company Schweitzer-Mauduit (NYSE: SWM) fell as much as 18% on huge volume in intraday trading today.

So what: Why the swooning stock price? There's no news out on the company, so it's unlikely that it's fundamental issues. Schweitzer-Mauduit's stock, however, has a very low average trading volume, so if there are any larger institutional investors looking to reduce or eliminate their positions, it could create significant selling pressure.

Now what: Schweitzer-Mauduit's primary business is tobacco. Roughly 90% of its sales come from tobacco products, and the company counts Philip Morris International (NYSE: PM), Altria (NYSE: MO), and British American Tobacco (NYSE: BTI) among its top customers. While today's selling pressure may give current shareholders a sinking feeling in their stomachs, savvy investors will keep their focus on the company's fundamentals and the intrinsic value of the business rather than the movements in the stock price.

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