U.S. stocks rose strongly Thursday, building on a three-day winning streak, as investors assessed more quarterly corporate results and solid U.S. economic data. In U.S. economic news, jobless claims fell unexpectedly to 779,000 last week, a two-month low but still a highly elevated level. Productivity plunged in the fourth quarter of 2020, decreasing at its sharpest pace since 1981, but the overall productivity trend is healthy. Factory orders rose 1.1 percent in December, indicating manufacturing should be healthy in the near term despite some indications of slowing momentum. The U.S. dollar strengthened to a two-month high against a basket of currencies after data pointed to an improvement in the U.S. economic outlook. Gold fell sharply, dropping below the psychological $1,800 level, on the stronger dollar and higher U.S. Treasury yields. Futures lost 2.4 percent to $1,791.20 an ounce on the New York Mercantile Exchange. Oil climbed on positive U.S. economic data, falling crude inventories, and the OPEC+ decision to adhere to output cuts, but gains were limited by the stronger dollar. West Texas Intermediate (WTI) crude futures advanced 0.6 percent to $56.02 a barrel. The Dow Jones industrial average rose 332.26, or 1.1 percent, to 31,055.86. Twenty-seven of the index's 30 components gained, led by financials Visa, Travelers, and American Express, which each surged at least 3.7 percent. Health-insurance giant UnitedHealth led decliners, dropping 2.5 percent. The broader Standard & Poor's 500 index rose 41.57, or 1.1 percent, to 3,871.74. Energy and financials were the best performing sectors. The technology-heavy Nasdaq composite index rose 167.20, or 1.2 percent, to 13,777.74. Online auctioneer eBay jumped more than 10 percent on strong quarterly results and a better-than-expected forecast. PayPal surged more than 6 percent on strong quarterly results. Apple gained 2.6 percent on a report it will make driverless cars with Hyundai, Netflix climbed 2.4 percent, and Facebook added 0.6 percent. Google-parent Alphabet declined 0.25 percent, while chipmaker Qualcomm dropped more than 7 percent after its quarterly revenue missed estimates.