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 oil and natural gas producer Berry Petroleum (NYSE: BRY) hit a gusher today, jumping as much as 10.4% on fairly heavy trading volume.

So what: A just-published market report from Credit Suisse highlights Berry and five other petroleum stocks as undervalued producers in American oil-production fields. Berry jumped the highest out of the six stocks in Credit Suisse's spotlight, followed by strong single-digit gains for Petrohawk Energy (NYSE: HK) and Rosetta Resources (Nasdaq: ROSE).

Now what: That threesome also happened to be the three most expensive stocks out of the six listed papers, judging on a P/E basis. The oil reserves in Texas and South Dakota, where Credit Suisse sees the most promise at the lowest market valuation, offer high returns on invested capital, and their developers have been unfairly punished in recent months. However, you should note that Berry sports some of the thinnest margins in the industry and only middling revenue growth. In that light, Berry seems like more of a gamble than wide-margined Rosetta or fast-grower Petrohawk.

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

Fool contributor Anders Bylund holds no position in any of the companies discussed here. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool is investors writing for investors.