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 Ion Geophysical (NYSE:IO) dropped as much as 36% in early trading before settling into a 20% drop today, driven by a disappointing earnings report.

So what: Revenue dropped a whopping 41% in the third quarter to $79.8 million and the company swung to a loss of $202.1 million. Adjusting for restructuring and special items, the company lost $20.1 million, or $0.13 per share, which was still below an expected profit of $0.05 per share.  

Now what: Weak demand and oversupply in Ion Geophysical's markets is causing the financial weakness and it doesn't look like demand will pick up quickly. The company is stopping investment in new programs, which is never a good sign for a company's future. I'm definitely not a buyer on the weakness and while I like the energy service market I think there are better buys available.