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 LDK Solar (NYSE: LDK) surged more than 10% after analysts at Goldman Sachs put peer First Solar (Nasdaq: FSLR) on their "conviction buy" list and set a price target of $165 per share, Indie Research reports.

So what: LDK has twice rallied more than 10% over the past week, with the last pop coming Jan. 18. Street enthusiasm for solar stocks is partially fueled by the possibility of Germany reducing tariffs on solar imports. Germany accounted for 15% of LDK's revenue in 2009.

Now what: The trouble with buying on speculation is that nothing's confirmed. Much as I believe the rumors about Germany, and for as much as I like solar over the long term, the market has handsomely rewarded so many of these issues over the past year that any bad news could cripple today's LDK buyers.

But that's only if you believe LDK is overpriced at current levels. I'm not so sure. Like peer GT Solar (Nasdaq: SOLR), the stock trades for less than 10 times the long-term earnings growth rate analysts expect.

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