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 gas prospecting technologist ION Geophysical (NYSE: IO) went down in flames today, falling as much as 30.4% from Tuesday's closing price -- but first jumping more than 14% in after-hours trading on Tuesday. Needless to say, all of this took place amid heavy trading volume.

So what: Tuesday's second-quarter report was just fine; both earnings and sales fell short of analyst targets, but CEO Bob Peebler promised a much stronger back half of the year. As I've said, Ion's shares actually jumped sky-high at the news. The drop came as Peebler announced his retirement this morning.

Now what: Oh, the drama! CFO Brian Hanson takes the CEO wheel as of January 1, 2012, while continuing as CFO and COO until further notice. The market reaction shows how much ION shareholders appreciate Peebler's business acumen, or perhaps how little faith they have in a numbers guy running the business. If a Peebler-less ION sounds scary, you can still profit from rising oil prices by shifting your energy-sector budget into drillers and service specialists such as Gulfmark Offshore (NYSE: GLF), Transocean (NYSE: RIG), and Schlumberger (NYSE: SLB). Read this free report to learn why three Fool analysts put real cash into each of these stocks.

Interested in more info on ION Geophysical? Add it to your watchlist.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.