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 Idenix (Nasdaq: IDIX) surged more than 11% in early trading before closing up 4.7% for the day. A William Blair analyst named the company as a likely buyout candidate while upgrading the stock to "outperform" from "market perform" in a new report.

So what: Idenix and Inhibitex (Nasdaq: INHX) each rallied on the report, in which analyst Y. Katherine Xu said the market for hepatitis C treatments would expand rapidly before peaking at $18 billion by 2024. Both companies compete with Pharmasset (Nasdaq: VRUS) in developing hepatitis C drugs.

Now what: Xu has a point. Last week, Gilead Sciences (Nasdaq: GILD) announced plans to acquire Pharmasset for $11 billion. Of the two, only Inhibitex commands more than $1 billion in market value as of this writing. Would either company command as much as Pharmasset in a buyout? Please weigh in using the comments box below.

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Fool contributor Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team. He didn't own shares in any of the companies mentioned in this article at the time of publication. Check out Tim's portfolio holdings and Foolish writings, or connect with him on Google+ or Twitter, where he goes by @milehighfool. You can also get his insights delivered directly to your RSS reader.

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