Even in the aftermath of an exciting weekend of economic action, the Monday blues ended up prevailing on Wall Street today. Listening to the news on Sunday night, you would've heard about a "rescue" in Spain and thought that it somehow solved every single problem on the Continent. Yet after some initial buying, investors woke up and realized that plenty of other troubles are still in front of European governments and stock markets. As a result, the Dow Jones Industrials (INDEX: ^DJI) swung wildly and reversed a big gain to end up falling well over 1% by the close.

If you've followed the Dow closely, you can probably guess that economically sensitive stocks were among those hit worst by the declines. Bank of America (NYSE: BAC) tried to improve its corporate image by announcing its pledge to lend $50 billion over the next 10 years toward green energy products, but it closed down more than 3% as investors still perceive the bank as being weak enough to be threatened by systemic shocks from Europe. JPMorgan Chase (NYSE: JPM) also fell 2.5%, even as some predicted that both it and B of A could benefit from increased regulation of savings and loan institutions that could make mortgages harder to get and lead to higher rates that could benefit mortgage lenders.

Hewlett-Packard (NYSE: HPQ) also fell nearly 3.5% after an analyst report pointed to slowing industrywide sales of PCs in the current quarter. Although CEO Meg Whitman is trying to transform HP into a more widely diversified business with strength in higher-margin areas, hardware like PCs and printers still make up a huge portion of HP's current business, and any weakness there has a big impact on the company overall.

Finally, Caterpillar (NYSE: CAT) was down almost 3%. Caterpillar's prospects center more on the U.S. and China than on Europe, but as the global economy becomes more interconnected, it's increasingly difficult to compartmentalize companies by geography -- especially in economically sensitive industries. If China holds up better than most fear, then the recent drop that has clipped off more than a quarter of its stock price so far could reverse itself quickly.

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