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: After a previous pop yesterday, shares of Molycorp (NYSE: MCP) soared more than 11% again today, after Chinese officials discussed plans to reduced exports of rare-earth metals. Unnamed officials quoted by the China Daily said exports could decline by as much as 30%.

So What: Molycorp is one of the few companies outside China that's mining rare earth oxides, which are used to create batteries, certain ceramics, and lasers. Its customer list includes Albemarle (NYSE: ALB) and W.R. Grace (NYSE: GRA). If China cuts production as promised, development-stage Molycorp could see significant outside investment in order to restart production at its primary mine in Mountain Pass, Calif.

Now What: Molycorp is virtually the prototype for what we call an informed speculation. If you choose to invest, do so knowing that, like a biotech, the company will need plenty of funding to build a sustainable business. And even then, there are no guarantees.

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