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 mobile patent peddler VirnetX (AMEX: VHC) took a nosedive today, falling as much as 26.5% on batches of heavy volume with quiet periods in between.

So what: The stock is hitting 52-week lows on news that the U.S. Patent and Trademark Office is re-examining a key VirnetX patent related to secure communications over wireless networks. The action seems to be a response to Apple (Nasdaq: AAPL) asking for this patent to be investigated in mid-July.

Now what: The majority of patents under the microscope of re-examination get overturned, and I don't much like VirnetX's business model to begin with. That said, Microsoft (Nasdaq: MSFT) played the examination card in previous VirnetX proceedings, and ended up settling that case for a cool $200 million anyway. The patent currently under review has the same name as one of the Microsoft pieces, yet it's not the same patent.

Given the company's highly concentrated patent portfolio, its financial future could live or die with the health of a handful of crucial papers. From here, the whims of the patent office will determine whether VirnetX crashes further or rebounds to insane new highs. This one's strictly for the gamblers out there.

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Fool contributor Anders Bylund holds no position in any of the companies discussed here. The Motley Fool owns shares of Apple and Microsoft. Motley Fool newsletter services have recommended buying shares of Apple and Microsoft. Motley Fool newsletter services have recommended creating a bull call spread position in Microsoft and Apple. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool is investors writing for investors.