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 midstream petroleum services provider Semgroup (NYSE: SEMG) soared as high as 12.4% in heavy intraday trading.

So what: The company just announced that it is handing off much of its SemStream liquid natural gas assets to natural-gas specialist NGL Energy Partners (NYSE: NGL). In return, Semgroup gets a 33% ownership stake in NGL Energy Partners, a $100 million cash payment, and two seats on the board of NGL's majority-owner partnership.

Now what: The move bolsters Semgroup's balance sheet while streamlining the business model. The company should turn around and invest the newfound cash cache in small-scale acquisitions and infrastructure investments soon enough. Semgroup's shares recently fell as far as 47% from 52-week highs set in the spring, making this move a part of a larger turnaround bounce.

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