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 Walter Energy (NYSE: WLT) jumped 10% briefly today on more buyout rumors.

So what: Yesterday, shares jumped on a report out of London's Independent that BHP Billiton (NYSE: BHP) or Anglo American were preparing bids to buy the company. Today, Australia's newspaper The Australian stoked the fire and continued yesterday's speculation.

Now what: There wasn't a lot of new information in The Australian article, so investors buying on that news are a little late to the party. But like I said yesterday -- buying simply on rumor is a terrible way to invest.

Analysts did react last night and don't seem to think the Walter/BHP deal makes a lot of sense; shares have been selling off all day. The euphoria is starting to die, and I don't see shares holding at elevated levels unless a deal is actually announced.

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This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.