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 silica producer U.S. Silica Holdings, Inc. (SLCA) dropped as much as 16% after the company announced preliminary fourth-quarter earnings.

So what: Management gave a peek into earnings and said revenue would be $149.5 million with net income of $0.31 per share. The top line is in line with estimates but analysts expected $0.43 per share in earnings so that's where the disappointment comes from today.  

Now what: We won't know more detail until February 25 when final fourth-quarter numbers are announced but management already pointed to winter storms impacting results. Bad weather led to higher costs as well as fewer well completions and that's likely the cause of the disappointing earnings-per-share figure. Early comments look like this is a onetime challenge, not a structural impact, but we won't know that until late February.