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 Stage Stores (NYSE: SSI) jumped 12% today on a spike in volume.

So what: Almost a million shares have traded hands so far today, nearly four times the three-month average. But there isn't any news out about the company or any press releases, so the reason for the move is a bit of a mystery.

Now what: When a stock moves this much with little or no news, I get alarm bells going off in my head. Maybe traders know something we don't, but there just isn't a solid reason to buy into this move today. I'm going to stick to the sidelines, as a speculative move just isn't something this Fool wants to be betting on.

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