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 manufacturer Century Aluminum Co (NASDAQ:CENX) jumped as much as 16% this morning after it reported better than expected earnings.

So what: Revenue jumped 40% to $587.9 million and the company swung from a net loss in last year's first quarter to net income of $73.8 million, or $0.76 per share. Analysts had expected an improvement from a year ago, but they estimated $576.9 million in revenue and $0.63 per share in earnings.  

Now what: Management said that strong demand in the U.S. and some signs of growth in Europe are helping operations. But China remains a wild card and could flood the market with product, as it's done with other commodities like steel recently. I would be cautiously optimistic about Century Aluminum Co, and with a forward P/E ratio of 9, the stock seems fairly priced given the risk. But commodity markets can change on a dime, so keep an eye on pricing trends because the first-quarter profit could evaporate quickly.