Stocks rebounded from a two-day sell-off as positive earnings reports fueled optimism about the economy. The Dow Jones Industrial Average (DJINDICES: ^DJI) and the S&P 500 (SNPINDEX: ^GSPC) both posted strong gains. Today's stock market Index Percentage Change Point Change Dow 0.80% 187.08 S&P 500 0.82% 21.02 Data source: Yahoo! Finance. Consumer stocks led the market today, with the Consumer Staples Select Sector SPDR ETF (NYSEMKT: XLP) gaining 1.4%. Technology companies had a big day; the Technology Select Sector SPDR ETF (NYSEMKT: XLK) likewise rose 1.4%. As retail companies report third-quarter results, their stocks are seeing big swings. Wal-Mart Stores (NYSE: WMT) rose sharply when it beat expectations, and Best Buy (NYSE: BBY) dropped when it fell short. Image source: GEtty Images. Wal-Mart continues its strong run Wal-Mart reported better-than-expected third-quarter earnings this morning and raised the outlook for the full year, sending shares of the retail giant soaring 10.9% to an all-time high. Revenue rose 4.2% to $123 billion, above the $121 billion analysts were looking for, and adjusted earnings per share came in at $1.00 compared with expectations of $0.97 per share. EPS guidance for the full fiscal year, which ends Jan. 26, was raised 1.6% at the midpoint to a range of $4.38 to $4.46. Comparable-store sales in the U.S. were particularly strong, with growth of 2.7% excluding fuel, compared with guidance given three months ago of a range of 1.5% to 2%. Grocery sales were a highlight, up low single digits. But the company showed strength in the top line across the board, growing e-commerce sales 50% and international revenue 2.5%, excluding currency effects. Profit margins fell as the company priced aggressively to boost traffic and the e-commerce business became a greater proportion of the total. Gross margin fell 29 basis points, and operating income in constant currency fell to 3.8% of revenue from 4.3% last year. With investors concerned over competition from Amazon.com and looking for clues about the upcoming holiday season, Wal-Mart's strong results and upbeat guidance for the end of the year were welcome news. Best Buy disappoints on Q3 sales, Q4 profit outlook Electronics retail chain Best Buy reported third-quarter results today that slightly missed revenue expectations and met predictions for earnings per share. However, guidance for fourth-quarter profits came in below analysts' consensus estimate, and the market sent shares down 3.6%. Revenue grew 4.2% to $9.32 billion, below analysts' expectation of $9.36 billion. Non-GAAP EPS was up 30% to $0.78. Comparable-store sales grew 4.5% in the U.S. and 4.4% overall. The company also gave a boost to its guidance for full-year revenue and operating profit. It now forecasts revenue growth of 4% to 4.8%, compared with earlier guidance of 4%. The outlook for non-GAAP operating income was raised to a range of 7.5% to 9.5% from the earlier guidance of 4% to 9%, but the EPS guidance for Q4 of $1.89 to $1.99 fell short of the analyst consensus of $2.03. Wall Street prognostications aside, CEO Hubert Joly was upbeat about the holiday season. "Looking ahead, we are very excited about our plans for holiday, including a curated assortment of great new technology products, free shipping with no minimums, and a range of new capabilities such as our new in-home advisor program, an updated gift center, and same-day delivery in 40 cities," he said in the press release. The revenue miss was blamed on the delayed launch of the iPhone X and the impact of hurricanes, decidedly short-term issues. But investors are particularly nervous about retailers these days, and it doesn't take much of a short-term disappointment to trigger some selling. Offer from The Motley Fool: The 10 best stocks to buy nowMotley Fool co-founders Tom and David Gardner have spent more than a decade beating the market. In fact, the newsletter they run, Motley Fool Stock Advisor, has tripled the S&P 500!* Tom and David just revealed their ten top stock picks for investors to buy right now. Click here to get access to the full list! *Stock Advisor returns as of Nov. 6, 2017.John Mackey, CEO of Whole Foods Market, an Amazon subsidiary, is a member of The Motley Fool's board of directors. Jim Crumly owns shares of AMZN. The Motley Fool owns shares of and recommends AMZN. The Motley Fool has a disclosure policy.