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 Yingli Green Energy (NYSE: YGE) surged more than 12% after three analysts upgraded their ratings on the stock, Barron's reports.

So what: Piper Jaffray upgraded Yingli to “overweight,” while Avian Securities bumped the stock from “negative” to “positive.” Still skeptical, HSBC would only upgrade Yingli from “underweight” to “neutral.” Impressive second uarter results apparently weren’t impressive enough for analysts there.

Now what: Common investors nevertheless piled into the stock, unsurprising when Chinese peers JA Solar (Nasdaq: JASO) and LDK Solar (NYSE: LDK) reported underwhelming second quarter results and disappointing guidance. Yingli also trades for less than half of the long-term earnings growth rate analysts expect. Most signs point to a bargain -- even with today’s rally. Do you agree? Would you buy at these levels? Weigh in using the comments box below.

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Fool contributor Tim Beyers is a member of the Motley Fool Rule Breakers stock-picking team. He didn’t own shares in any of the companies mentioned in this article at the time of publication. Check out Tim's portfolio holdings and Foolish writings, or connect with him on Google+ or Twitter, where he goes by @milehighfool. You can also get his insights delivered directly to your RSS reader.

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