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 FireEye (MNDT) soared 24% today after the cybersecurity technologist agreed to acquire rival Mandiant Corp. in a deal worth about $1 billion.

So what: The deal follows Cisco System's (CSCO -0.88%)$2.7 billion buy of Sourcefire in October, reinforcing the recent trend of massive consolidation in the cybersecurity space. FireEye is making the move to expand its footprint, and judging by the stock's big pop today, Mr. Market is particularly pleased with the price management is paying to do it.

Now what: FireEye will issue an aggregate of 21.5 million shares and options to buy shares of FireEye stock, and will pay $106.5 million of net cash in the transaction to Mandiant security holders. "Organizations today are faced with knitting together a patchwork of point products and services to protect their assets from advanced threats," said FireEye Chairman and CEO David DeWalt. "Together, the size and global reach of FireEye and Mandiant will enable us to innovate faster, create a more comprehensive solution, and deliver it to organizations around the world at a pace that is unmatched by other security vendors." Of course, with FireEye shares surging to a new 52-week high today and trading at a price-to-sales of almost 40, I'd wait for a wider margin of safety before betting on it.