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 network security expert Fortinet (Nasdaq: FTNT) are soaring as high as 30% over last Friday's closing price today.

So What: Rumor has it that IBM (NYSE: IBM) is in serious discussions to acquire the company, which would trigger a hefty buyout premium. Neither Fortinet nor Big Blue are willing to comment on the subject, but the rumor does seem plausible in the context of recent buyout action in the security field, not to mention the company's high-quality business results.

Now What: The problem with rumors is that they sometimes become their own undoing. By juicing Fortinet's share price this high, an already-expensive stock suddenly becomes outright overpriced, which may scare IBM or other potential buyers away. Conversely, basing a buyout bid on earlier price levels might not convince shareholders to vote the deal through the acceptance stage. Whether or not you believe in this rumor, selling out now could be the best move available before the other shoe drops.

Interested in more info on Fortinet? Add it to your watchlist.

Fool contributor Anders Bylund holds no position in any of the companies discussed here. The Fool owns shares of IBM. 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.