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: Oil and natural gas exploration company Approach Resources (Nasdaq: AREX) fell as much as 10% in intraday trading Tuesday, yet recovered most of its losses for the second time in less than a week.

So what: With no news stories apparent involving the company, it appears today's move relates to the overall market weakness derived from the potential for a nuclear crisis in Japan. Oil, which could wind up being a fuel source Japan turns to in droves once the bigger picture seems clearer, is also down considerably today.

Now what: After reporting quarterly results late last week and receiving a downgrade from Hilliard Lyons from buy to long-term buy, its stock price has been bouncing around like a superball. The company's stock has had a tremendous run, which I noted last week, but a lot of question marks still remain. Approach Resources' quarterly report detailed a large expected jump in spending this year, and I'm worried about the potential margin crunch from that increased spending. The company's stock is also closely tied to the price of West Texas Intermediate crude. If oil continues to pull back, it's likely that Approach Resources will follow.

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

Fool contributor Sean Williams does not own shares in any companies mentioned in this article. You can follow him on CAPS under the screen name TMFUltraLong.

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