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 natural-gas-focused partnership Eagle Rock Energy Partners (Nasdaq: EROC) shot up as much as 19% in intraday trading on heavier-than-average volume.

So what: When a company announces its acquisition of a publicly traded target, you can expect to see the latter's stock rise. But it's far more unusual to see the acquirer's shares increase -- much less to the degree that Eagle Rock's did today. After the close of trading yesterday, Eagle Rock announced that it will acquiring privately held Crow Creek Energy, a natural gas company with 268 Bcfe of proved reserves, for $318 million in cash and stock. Eagle Rock will also assume $207 million in debt.

Now what: The acquisition seems to be a good fit for Eagle Rock, and management noted that it continues the company's focus on building its upstream and midstream businesses. While I'm always cautious about chasing a big gain like this, with a perfect five-star rating from The Fool's CAPS community and an eye-catching 5.8% distribution rate, Eagle Rock could be worth a closer look.

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