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 Magnum Hunter Resources (NYSE: MHR) dropped as much as 27% today after the company dropped its auditor.

So what: It was disclosed late yesterday that Magnum Hunter has dismissed PricewaterhouseCoopers as its auditor. The auditor said it had found material weakness in internal controls and had requested additional information about the value of the company's oil and gas assets.

Now what: The moment an auditor discloses material weakness, investors run for the hills, so that's a big part of the move today. What's concerning for investors is that the company dismissed the auditor instead of solving the reported problems, a sign that maybe accounting standards aren't up to par. I'd stay far, far away from this stock, because any time a company fires an auditor or finds weakness in accounting procedures, there's trouble coming.

Interested in more info on Magnum Hunter Resources? Add it to your watchlist by clicking here.