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: MEMC Electronic Materials (NYSE: WFR) dropped 14% in intraday trading today, after issuing disappointing earnings and guidance.

So what: Second-quarter non-GAAP EPS of $0.01 badly missed the $0.06 consensus estimate and fell 83% year over year. Revenue of $746 million grew 66% year over year, helped by the resolution of a long-term wafer supply agreement with Suntech Power Holdings. Excluding the Suntech resolution, revenue grew 33%.

Now what: Management blamed the disappointing results on "a sharp slowdown and weaker pricing in solar wafer markets and a modest softening of underlying semiconductor demand." Despite cost-cutting actions in response to the weak environment, 2011 guidance was lowered to non-GAAP revenue of $3.3 billion to $3.6 billion, and non-GAAP EPS of $0.80 to $1.00. Prior guidance called for $3.4 billion to $3.7 billion, and $1.00 to $1.30, respectively, while the consensus forecast predicted $3.4 billion and $0.90.

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