Apple's plunge on disappointing earnings pulled the Nasdaq lower in early trading Wednesday, but stronger economic indicators buoyed the markets overall, pushing the other key indices well into positive territory.
At 11 am (1600 GMT) the Dow Jones Industrial Average was up 80.16 (0.58 percent) to 13,859.49.
The broad-based S&P 500 was up 5.18 (0.35 percent) to 1,499.99.
The tech-heavy Nasdaq Composite was down 5.67 (0.18 percent) to 3,148.00.
US jobless claims came in well below expectations, an unexpectedly strong result for the second week in a row.
Chinese manufacturing activity in January was also strong, suggesting the world's second-biggest economy is moving into better times.
But shareholders of Apple, the biggest US company by market capitalization, drove shares lower after the company disappointed the market with below-expected revenues and a middling outlook on upcoming revenues.
Shares were down 10.3 percent to $461.26, far below the $700 peak level Apple reached last year.
Apple reported quarterly profits of $13.1 billion on revenue of $54.5 billion, but it forecast that its revenue for the current quarter would range from $41 to $43 billion.
Briefing.com analyst Patrick O'Hare predicted Apple would dominate the market's mindset Thursday as participants question "whether the company's best growth days are indeed behind it."
Apple's woes were particularly striking in light of earlier strong quarterly earnings reports from technology titans IBM and Google, both of which surged on Wednesday.
On Thursday, Google was up 1.5 percent while IBM gained 0.1 percent.
Netflix, which topped its subscriber growth forecast and posted strong profits, rose 36.8 percent.
Conglomerate 3M reported in-line profits; shares were up 0.2 percent.
Defense contractor Lockheed Martin reported earnings that fell short of analyst expectations, but projected that 2013 profits would come in above the 2012 levels.
A company statement acknowledged Lockheed faces the "uncertainty" of possible defense cuts in Washington. Shares were off 2.5 percent.
Flying giant United Continental, which sustained a loss for 2012, rose 3.9 percent after reporting revenues that bested expectations.
Biotechnology giant Amgen offered a 2013 outlook that bested expectations, but shares fell 0.3 percent following lower 2012 profits.
Bond prices fell. The yield on the 10-year US Treasury rose to 1.86 percent from 1.83 late Wednesday. The 30-year yield rose to 3.05 percent from 3.03. Bond prices and yields move inversely.