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 engineered products manufacturer SPX Corp. (NYSE: SPW) were diving today, losing as much as 15% on heavier-than-average volume.

So what: SPX's second-quarter results certainly didn't look like anything that would kneecap the stock. Revenues were up 16% from last year, to $1.38 billion. On the bottom line, the year-over-year comparison was hurt by a charge in this year's quarter and a tax benefit last year. Adjusting for those items, per-share profit was $0.91 versus $1.00 in 2010. Analysts were expecting $0.89 in earnings per share on revenue of $1.34 billion.

Now what: Though current results topped estimates, investors were hoping for more from the company's forward guidance. Management left its full-year profit forecast fixed at a midpoint of $4.40, which is short of the $4.57 that Wall Street had been expecting. Meanwhile, management estimated $1.00 to $1.10 in earnings per share for the third quarter, notably shy of the $1.48 analysts had in mind.

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