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 petroleum producer and explorer Cabot Oil & Gas (NYSE: COG) hit a gusher today, jumping as much as 11.4% on very heavy volume.

So what: Like your home value rising on a big-ticket sale in the neighborhood, Cabot jumped on buyout action closely related to the Eagle Ford Shale where this company makes much of its living. BHP Billiton (NYSE: BHP) is paying a generous 65% premium for Petrohawk Energy (NYSE: HK).

Now what: The deal gave a lift to the entire field of Eagle Ford operators, including as much as a 7.4% jump for sector giant Chesapeake Energy (NYSE: CHK) and a 6.4% boost for Magnum Hunter Resources (NYSE: MHR). Cabot set a fresh all-time high in intraday trading and shares have now doubled in value over the last year. However, fellow Fool Isac Simon notes that Cabot stock looks expensive compared to sector rivals and suggests keeping your hands off of it.

Interested in more info on Cabot Oil & Gas? Add it to your watchlist.

Fool contributor Anders Bylund holds no position in any of the companies discussed here. Motley Fool newsletter services have recommended buying shares of Chesapeake Energy. Try any of our Foolish newsletter services free for 30 days. 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.