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 Oasis Petroleum (NYSE: OAS) fell as much as 11% today as shares were downgraded by an analyst and oil drained further.

So what: Oil has dripped another 2.4% today, which applies new pressure on oil and gas companies. But the bigger driver earlier in the day was a downgrade of Oasis' shares from buy to hold by Wunderlich.

Now what: Falling oil prices are much more troubling in the long term because profits will be under major pressure if the decline continues. I would be cautious buying in right now. The economic concern in Europe, as well as a continuation of downward momentum in oil, is driving short-term stock prices right now. Once that settles, shares may be worth jumping on, but I would like to see the market calm down before trying to catch a falling knife.

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