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 independent oil refiner Western Refining (NYSE: WNR) rose 15.5% in intraday trading today after a Wall Street analyst upgraded the stock.

So What: Because Western Refining implemented restructuring initiatives that involve heavy deleveraging and refocused its portfolio on higher-return markets, Morgan Stanley upgraded it to overweight with a $9.00 price target. With Western Refining poised to cut its debt load by more than half in 2011, Morgan Stanley also believes the shares deserve to trade at less of a discount to rivals Holly (NYSE: HOC) and Frontier Oil (NYSE: FTO).

Now What: Even with today's pop, there's still about 40% worth of upside to Morgan Stanley's $9.00 price target. Of course, when you couple Western Refining's restructuring efforts with the fact that even integrated giants like ExxonMobil (NYSE: XOM), Chevron (NYSE: CVX), and ConocoPhillips (NYSE: COP) all have strengthening refining margins, the stock has some serious multibagger potential, to boot. I'd feel uncomfortable about jumping in today, but any pullback should be considered a long-term entry point.

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