Forget Facebook. This is still Apple's stock market.

Apple _ the world's most valuable company _ climbed nearly 6 percent on Monday, helping propel major U.S. stock indexes to gains after a week of losses. The Standard & Poor's 500, where Apple accounts for 4 percent of the index, enjoyed its best day in nearly five weeks. The Nasdaq composite index, where Apple accounts for an even heftier 12 percent, notched its biggest gain of the year.

And it was no thanks to Facebook. The social networking giant, on its second day as a public company, plunged 11 percent to $34.03, even as the rest of the market rallied.

It was tough to pin down any surefire reason for Facebook's stock decline. It did go public during the market's worst week of the year so far, and finished Friday just 23 cents above its opening price of $38. But that didn't explain Monday's decline.

"There must have been some sober second thoughts about this," said Brian Wieser, an analyst at Pivotal Research Group who was first to come out with a "Sell" rating on Facebook's stock on Friday. He sees the stock as too expensive considering the risks associated with Facebook's brief history and unproven advertising model. His fair price, or "target price," is $30.

Apple is also no stranger to fickle investors. Its stock soared 57 percent from the end of last year through April 9, climbing to more than $636 from $405 as iPhone sales seemed unstoppable. Then it fell for most of April and May, declining to about $530 on Friday, partly because investors are worried that phone companies will grow tired of subsidizing the expensive phones to sell to customers.

But Monday's gain of $30.90 to $561.28 _ its second-biggest climb of the year so far _ came after several analysts said they expect its iPhone business to continue to do well.

The benchmark Dow Jones industrial average rose 135.10 points, or 1.1 percent, to 12,504.48. The S&P 500 rose 20.77 points to 1,315.99, and the Nasdaq jumped 68.42 to 2,847.21.

That was welcome relief after a month that has been crippled by Greece, which failed to elect a new government two weeks ago and is teetering close to leaving the euro.

Investors desperate for good news latched on to weekend statements from China's Premier Wen Jiabao, who promised to boost the country's growth, a shift from previous rhetoric that focused mainly on curbing inflation.

That drumbeat of bad news about Europe continued, but Apple helped investors shrug it off. The weekend's Group of Eight meeting of world leaders brought only an ambiguous conclusion, producing promises to pursue growth in Europe but little in the way of concrete plans for how to do so.

"I wish I could say the coast is clear," said Katherine Nixon, chief investment officer for Northern Trust's personal financial services unit in Chicago. But, "the G-8 didn't really solve anything." Continued...