U.S. stocks climbed on Monday, with the S&P 500 bouncing back from its biggest weekly drop since 2012, as companies including Berkshire Hathaway reported results.
"I've been a believer for months that every time we get a sell off, it's a buying opportunity," said Randy Frederick, managing director of active trading and derivatives at Charles Schwab.
Groupon rallied a day before the provider of online deals reports quarterly earnings, with other Internet names including Yelp and Facebook also surging.
Warren Buffett's Berkshire Hathaway gained after reporting better results at units including insurer Geico. Michael Kors Holdings declined after the handbag maker reported better-than-expected results, but said its profitability would fall in 2014. Walgreen shares climbed after the drugstore chain said its chief financial officer was leaving the company.
Of the 381 S&P 500 companies that have reported second-quarter results, 68.8 percent have beat estimates on earnings, and 64.1 percent have topped expectations for revenue, according to David Aurelio, research analyst at Thomson Reuters.
"The world's markets are celebrating the $6.6 billion rescue of Portugal's banking system," Jeffrey Saut, chief investment strategist at Raymond James, emailed of Portugal's plans to spend 4.9 billion euros, or $6.58 billion, to bail out Banco Espirito Santo.
"Alas, I wish it was just that simple," Saut added.
Major U.S. Indexes
After wavering between positive and negative terrain, benchmark indexes took a definitive turn higher as the session progressed.
After a 102-point leap that brought it temporarily back into positive terrain for the year, the Dow Jones Industrial Average gained 75.91 points, or 0.5 percent, to 16,569.28.
The rose 13.84 points, or 0.7 percent, to 1,938.99, with energy pacing gains and utilities the worst performing of its 10 major industry groups.
"Prior to the break below 1,950 support on the S&P 500 last week, we spent five weeks in about a 50-point range. It wouldn't be a surprise if we spent the next three-to-four weeks range bound between 1,950 and 1,900," Elliot Spar, market strategist at Stifel, Nicolaus & Co., emailed in afternoon commentary.
The Nasdaq gained 31.25 points, or 0.7 percent, to 4,383.89.
For every two shares falling, more than three rose on the New York Stock Exchange, where nearly 676 million shares traded. Composite volume topped 3 billion.
The CBOE Volatility Index (VIX), a gauge of investor uncertainty, fell nearly 12 percent to 15.
The dollar gained against the currencies of major U.S. trading partners and the 10-year Treasury yield used in figuring mortgage rates and other consumer loans fell a basis point to 2.488 percent.
Energy costs reversed course, with oil futures for September delivery rising 41 cents, or 0.4 percent, to $98.29 a barrel; gold futures fell, with the December contract falling $5.90 to $1,288.00 an ounce.
The VIX surged 34 percent last week, as the S&P 500 tallied its worst weekly loss since June 2012.
Read MoreWorst weekly drop for S&P 500 in more than two years
—By CNBC's Kate Gibson
Coming Up This Week:
Tuesday
Earnings: Disney, CVS Caremark, Archer Daniels Midland, MGM Mirage,Michael Kors, Cablevision, Scotts Miracle-Gro, Time Inc., Frontier Communications, Groupon, Potbelly, Take Two Interactive, FireEye, First Solar, Zillow, Liberty Interactive, Liberty Media, Regeneron, Activision Blizzard, Toyota
10:00 a.m. ISM nonmanufacturing
10:00 a.m. Factory orders
Wednesday
Earnings: Time Warner, Mondelez International, Chesapeake Energy, Devon Energy, Viacom, AOL, Molson Coors Brewing, Devon Energy, DishNetworks, Ralph Lauren, Transocean, 21st Century Fox, Keurig GreenMountain, CenturyLink, Jack in the Box, Zulily, ING
8:30 a.m. International trade
Thursday
Earnings: Wendy's, Orbitz, CBS, Monster Beverage, News Corp, Nvidia, Mylan Labs, AMC Networks, Zynga, Lionsgate, Sprouts Farmers Market, Windstream,Duke Energy, Sempra Energy, Stratasys, Teradata, Computer Sciences, GreatPlains Energy
Weekly chain store sales
8:30 a.m. Initial claims
3:00 p.m. Consumer credit
Friday
Earnings: Brookfield Asset Management, Buckeye Partners,Petrobras
8:30 a.m. Productivity and costs
10:00 a.m. Wholesale trade
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