Yesterday may have been the worst day the broad-based S&P 500 (SNPINDEX:^GSPC) had witnessed since April, but that's all forgotten today, with the index surging despite what would be perceived to be negative economic data.

On the data front, the Thomson Reuters/University of Michigan consumer sentiment reading for July decreased to 81.3 from a reading of 82.5 in June. This was well below expectations from economists, who had been expecting consumer sentiment to rise to around 84. Lower consumer sentiment signals that people feel less confident about some combination of their short- and long-term economic outlook, which is a potentially bad precursor for consumer spending, a big component of U.S. GDP.

Also, June's leading indicators rose by just 0.3%, when Wall Street's expectation was for an expansion of 0.5%. Similar to the weaker sentiment figures, this could signal that consumers' abilities to push the economy higher is waning, and we could be nearing a period of slower growth.

However, strong earnings reports from a number of technology stocks, as well as a strong defense of the biotech sector by ISI Group analyst Mark Schoenbaum, went a long way to help the S&P 500 reclaim nearly all of yesterday's lost ground. By day's end the S&P 500 ended higher by 20.10 points (1.03%), to close at 1,978.22.

Source; Simon Cunningham, Flickr.

Among individual stocks, none stood out as having a wilder day than China-based mobile security firm NQ Mobile (NYSE:NQ), which began the day by plunging more than 20%, only to finish higher by 15.2% after announcing that it had fired its auditor PricewaterhouseCoopers. NQ followed up its announcement with the hiring of Marcym Bernstein Pinchuk as its new independent auditor.

On one hand, as my Foolish colleague Steve Symington pointed out earlier today, it's great to see NQ Mobile bringing another reputable auditor on board, as it could cause investors who are concerned about the integrity of the company's financials to relax a bit. Then again, switching auditors following ongoing allegations of revenue overstatement from critics is only going to enhance the rumors that NQ hasn't been fully forthcoming with its deals. This continues to look like a situation you'll want to stay far, far away from for the time being.

Lagging not too far behind NQ Mobile is analog semiconductor product producer Skyworks Solutions (NASDAQ:SWKS), which roared higher by 14.1% after crushing its already boosted third-quarter results, and raising its fourth-quarter forecast. For the quarter, Skyworks reported a 35% increase in year-over-year revenue, to $587 million, well ahead of the $570 million guidance given last month and expected by Wall Street. Profit for the quarter jumped 54% to an adjusted $0.83 per share, as adjusted operating margins grew 480 basis points, to 30.5%. By comparison, the Street was only anticipating a profit of $0.80 per share in Q3.

If you're looking for a reason why Skyworks' results were so strong, look no further than Apple; its strong iPhone sales continue to provide the spark for Skyworks. As long as Skyworks remains innovative, it has a good chance of remaining a key components supplier for Apple.

Looking ahead, Skyworks announced that it sees fourth-quarter revenue up 43% year over year, to $680 million, with adjusted EPS rising 56% year over year, to $1. The consensus estimate had only been expecting Skyworks to earn $0.87 in EPS on $606.6 million in revenue. This was a blowout of epic proportions for Skyworks and, assuming it finds a niche in the upcoming iPhone 6, which I'd say is probably better than 50-50, it could have further room to run higher.

Lastly, telecom equipment and service provider Ericsson (NASDAQ:ERIC) tacked on 8.7% after it, too, reported better-than-expected quarterly results. For the quarter, Ericsson announced a 1% decline in revenue from the year-ago period, but did see its revenue improve 13% from the sequential first quarter. Gross margin, however, improved 400 basis points, to 36.4%, allowing its EPS to improve to 1.07 Swedish krona per share (or about $0.16 in U.S. dollar terms). Analysts have been expecting Ericsson to report only 1.02 in Swedish krona ($0.15), so this was a modest, but welcome, bottom-line beat for the telecom giant.

Investors really seemed to latch onto Ericsson's statement that it's seeing robust growth in the Middle East, China, and India, which have the potential to deliver decades of improved margins and profitability with Ericsson still scratching the surface in these regions. At just 14 times forward earnings following today's pop, Ericsson isn't particularly expensive; but given its lack of consistent top-line growth, I believe I'd be patient and stick to the sidelines for the time being.