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 Sourcefire (NASDAQ:FIRE.DL) soared a whopping 28% today after tech gorilla Cisco Systems (NASDAQ:CSCO) agreed to acquire the cybersecurity specialist for $2.7 billion. 

So what: The all-cash deal values Sourcefire at $76 per share and represents a premium of 29% to its closing price on Monday. Cisco is making the move to expand beyond its bread-and-butter networking gear business, naturally fueling speculation that other tech giants like IBM and EMC are looking to make a small cybersecurity purchase of their own.

Now what: The deal is expected to close in the second half of 2013 and will likely be slightly dilutive to Cisco's GAAP earnings in 2014. "Sourcefire aligns well with Cisco's future vision for security and supports the key pillars of our security strategy," said Cisco's vice president of corporate development Hilton Romanski. "Through our shared view of the critical role the network must play in cybersecurity and threat defense, we have a unique opportunity to deliver the most comprehensive approach to security in the market." So while Sourcefire's upside is likely limited at this point, another cybersecurity play like Fortinet -- which is up 5% on today's news -- might be a possible buyout target worth considering.