Everything was looking good for markets early today; coming off its best week all year, the Dow Jones Industrial Average (INDEX: ^DJI) jumped nearly 100 points just after the opening bell on reaction to Spain's banking bailout of as much of $125 billion. But the good times didn't last long: By 10:30 a.m. ET, the Dow was already in the red and fell consistently throughout the day to end down more than 1%.

Overall, investors became concerned that the bailout of Spain's banks isn't enough to address bigger, underlying issues in the eurozone. Will Spain itself need a bailout? And what happens if Greece leaves the eurozone after elections on June 17? We'll have a better answer to at least one of those questions in a week's time, but many areas of uncertainty still remain. This uncertainty was reflected in Spanish and Italian bond yields, which increased sharply as Spain's bank bailout seemed to bring up more questions than answers for investors.

Here's how three major U.S. indices fared on the day:

Index

Change

Ending Value

Dow Jones Industrial Average -142.97 [-1.14%] 12,411.23
Nasdaq -48.69 [-1.70%] 2,809.73
S&P 500 -16.73 [-1.26%] 1,308.93

Turning to individual stocks, Bank of America (NYSE: BAC) was the Dow's biggest loser today, continuing its wild volatility. The company is one of the more sensitive to Europe and the global economy, which helped drag it down 3.7% today. Fellow megabank JPMorgan Chase (NYSE: JPM) was also one of the Dow's biggest losers, dropping 2.6%. Investors are bracing this week for possible downgrades of both banks' bond ratings by Moody's, which is reviewing the ratings of 17 global banks.

Hewlett-Packard (NYSE: HPQ) was the second biggest loser on the Dow, dropping 3.5%. The company remains the worst performer on the Dow in 2012, down 16.9% year to date. HP has been notoriously slow to adapt to the shift to the high-growth area of mobile products, a space in which Apple (Nasdaq: AAPL) has eaten the company's lunch. Apple again showed its innovative spirit today, unveiling the new MacBook Pro, which it calls "the best computer Apple has ever made." The company also showed off its new Mountain Lion desktop operating system and iOS 6 mobile operating system. Alas, investors might have been expecting more from the tech giant, as shares finished down 1.6%.

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