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 infrastructure construction specialist MasTec (NYSE: MTZ) crumbled today, dropping as much as 16% on many times the average trading volume.

So what: Last night's second-quarter report showed 52% sales growth and 72% higher earnings, and the company also raised its full-year targets. Shares climbed more than 10% in aftermarket action, but then plunged through the trading floor this morning.

Now what: Let's just say that MasTec picked a terrible time to report good news: The entire market is in turmoil today, and the oil industry where MasTec collects many of its contracts is doing worse than most. Last night's pop only set this stock up for a steeper fall in today's panicked environment. By comparison, Shaw Group (Nasdaq: SHAW) fell 6.9% at its worst, Fluor (NYSE: FLR) dropped 8.6%, Foster Wheeler (Nasdaq: FWLT) sank 9.4%, and Chicago Bridge & Iron (NYSE: CBI) lost as much as 10%. Nobody is safe today -- perhaps it's time to go contrarian and pick up some high-quality construction firms on the cheap.

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