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 chip-manufacturing-equipment maker Mattson Technology (Nasdaq: MTSN) plunged 10% today on triple the stock's average trading volume.

So what: This move, while drastic for a single-day change, merely erased the gains of the last week or so. The market is nervous about semiconductor stocks on the eve of another earnings season, and this thinly traded stock appears to be the victim of a fearful overreaction today.

Now what: In fact, the only real news about Mattson in the last 24 hours was a large equipment order from a new customer in Asia -- a positive sign if anything. Mattson's small size next to giant rivals Applied Materials (Nasdaq: AMAT) and LAM Research (Nasdaq: LRCX) makes the stock prone to high volatility, as you can see by comparing price graphs of the three stocks. Though Mattson may look cheap today, I'd rather hear what chip giants such as Intel (Nasdaq: INTC) are planning in terms of capital investments before taking the plunge.

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