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It's easy to see why stocks should be weaker: We have had a string of economic numbers that have missed, earnings are flat quarter over quarter, and there is talk of deflation again.
What is clear is that a lot of marquee names are getting mauled this week, and I don't just mean Apple at a new low.
Caterpillar, for example, is at its lowest level since July.
Bank of America is now negative for the year.
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Then there are the big biotech guys. Stocks that have been going up all year have suddenly halted: Amgen , Biogen Idec, Gildead, Celgene. Not going down, just halted.
Still, don't kid yourself: Many would like to see a pullback. A lot of funds have missed this rally and wouldn't mind getting in at a lower price.
How far we have come in a week! It seems like that historic high for the S&P 500 was 5 years ago, no? But it's not. Even with the decline this week, we're still only 3.5 percent off the historic high in the S&P 500, which occurred ... uh ... exactly one week ago.
—By CNBC's Bob Pisani