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: VIVUS (Nasdaq: VVUS) shares plunged 10% in early trading before recovering later in the day.

So What: There weren't any company announcements today, so it appears this was not a news-driven event. In early trading there was incredibly high volume that settled down later in the day.

Now What: Options volume was unusually high yesterday in both puts and calls, so the stock's move back up today could have been profit-taking on options positions. VIVUS is waiting for a decision on Qnexa from the Food and Drug Administration, so investors are betting on a move, one way or the other. The advisory panel voted against Qnexa, so it may be a little early to jump on this stock until we hear more positive news.

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Fool contributor Travis Hoium does not have a position in any company mentioned. You can follow Travis on Twitter at @FlushDrawFool, check out his personal stock holdings, or follow his Motley Fool CAPS picks at TMFFlushDraw.

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