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 SemGroup (NYSE: SEMG) jumped as much as 20% today after the company received a buyout offer.

So what: Plains All American Pipeline LP (NYSE: PAA) has made a $1 billion hostile takeover offer for SemGroup public after being rebuffed by the company in the past. The offer, made Oct. 6, was for $24 per share, a premium at the time but a discount to SemGroup's current price.

Now what: Buyouts in the pipeline industry are hot right now after Kinder Morgan (NYSE: KMI) agreed to buy El Paso (NYSE: EP) in a $21 billion deal announced last week. Since SemGroup has brushed off buyout offers before, it's still unclear whether this will end in a buyout or whether SemGroup will remain an independent company. With shares trading nearly $4 higher than the most recent offer price, I would at least be inclined to take some profit off the table in case a higher offer doesn't materialize.

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