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 RealD (NYSE: RLD), whose gear is used to project and view 3-D images, fell more than 21% in early trading and remain down more than 15% as of this writing. The company failed to live up to Wall Street estimates for first-quarter revenue.

So what: For investors, this is just the latest in a string of brutal hits. RealD has suffered 10% or worse down days in May, June, and now twice in July. For the first time, the stock is trading below its IPO price of $16 a share.

Now what: RealD booked $59.6 million in revenue, down $64.5 million in last year's first quarter. Analysts were expecting $78.9 million, probably figuring on increased 3-D demand with the release of Time Warner's (NYSE: TWX) Harry Potter and the Deathly Hallows: Part 2 and Walt Disney's (NYSE: DIS) Captain America: The First Avenger. Management referenced both films in its earnings report. Neither was enough to carry sales to hoped-for levels. Does it matter? You tell me. Let us know what you think about RealD 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 owned shares of Disney and Time Warner 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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