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: Tuesday was a terrible day for solar power companies in general, and Chinese ones in particular. Yingli Green Energy Holding (NYSE: YGE) was swept up in the downtrend, with a 10.2% intraday fall from last night's close.

So what: Chinese interest rates got hiked 0.25% today, kicking off rumors that Beijing might let the yuan strengthen versus the U.S. dollar and other currencies. That move would force Chinese businesses like Yingli into a conundrum: raise prices to account for the relatively higher cost of making its solar panels, or live with lower profits instead.

Now what: The Chinese government has not officially stated any intention to raise the value of its currency, so I think you still have to treat this purported threat to Yingli's profitability as a rumor. There is ample reason to believe in a strong solar market in 2011. Yingli and fellow Chinese solar power experts LDK Solar (NYSE: LDK) and JA Solar Holdings (Nasdaq: JASO) -- both of which fell harder than Yingli today -- all look like potential buy-in situations today.

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