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 Chinese solar-wafer maker LDK Solar (NYSE: LDK) sank 10% Friday after its current-quarter and full-year outlook disappointed investors.

So what: LDK's revenue guidance cut for the second quarter was so dramatic -- it now sees $480 million to $500 million versus the previous guidance of $710 million to $760 million -- that investors are going to have a tough time banking on management's future guidance. When you couple those credibility issues with the strong industry tailwinds also being felt by peers like JA Solar (Nasdaq: JASO), today's drop seems justified.

Now what: I'd continue to keep my distance from LDK. Management also cut its full-year revenue outlook to about $2.6 billion from $3.6 billion, and with such a heavy debt load, investors are also worrying about the company's long-term viability. For investors who really want some solar exposure, the more financially sound and operationally healthy Yingli Energy (NYSE: YGE) seems like a better bet.

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