NEW YORK (Bloomberg) US technology stocks rallied on improving earnings, sending the Nasdaq-100 Index to a ten-year high and extending a weekly gain for the Standard & Poor's 500 Index, while lower-than-estimated results at Caterpillar Inc. dragged the Dow Jones Industrial Average lower.Advanced Micro Devices Inc. rose 19 percent, the most since November 2009, after the chipmaker forecast more sales than analysts estimated. Technology stocks in the S&P 500 gained 1.2 percent, the most among 10 industries. Caterpillar slid 5.8 percent as profit trailed projections because of Japan's record earthquake and slower demand from China. C.R. Bard Inc. declined 12 percent, the biggest loss in the S&P 500, after sales missed projections.The S&P 500 rose 0.1 percent to 1,345.02 at 4pm in New York and gained 2.2 percent this week. The Dow Jones Industrial Average dropped 43.25 points, or 0.3 percent, to 12,681.16. Gains in technology stocks pushed the Nasdaq-100 Index up 1.1 percent to the highest level since February 2001.“You’re seeing fast money gravitate to the large-cap tech names, viewing them as better able to withstand slower economic growth,” said Mark Bronzo, who helps manage $26 billion at Security Global Investors in Irvington, New York in a telephone interview. “There are a couple stocks weighing on the Dow where the earnings came out a little less than expected but overall, earnings have been pretty good.”Stocks surged on Thursday after euro-area leaders eased the terms of loans for cash-strapped nations and announced the latest aid for Greece after eight hours of talks yesterday. Officials empowered their 440-billion euro ($635 billion) rescue fund to buy debt across stressed nations, helping to erect a firewall around Spain and Italy even as they risked temporary default to lighten the Greek debt burden.“Policy makers have made an important step,” Jeffrey Palma, global equity strategist at UBS AG, said in an interview on Bloomberg Television's “In the Loop”.“Is this the be-all, end-all package? No, and I think we need to be concerned still that there are medium-term challenges, but I do think it eliminates some of those tail risks.”The S&P 500 has declined 1.4 percent from an almost three- year high in April amid speculation that the sovereign debt crisis in Europe is spreading and concern that US lawmakers will fail to reach a deal on raising the nation’s debt limit before the August 2 deadline.Quarterly reports from corporations have helped boost US stocks this week. Among 122 S&P 500 companies that have reported earnings since July 11, 83 percent exceeded the average analyst estimate, according to data compiled by Bloomberg.Technology companies rallied, with semiconductor makers rising 1.6 percent for the biggest S&P 500 gain among 24 industries. AMD jumped 19 percent to $7.75, the largest gain in the index. The second-largest producer of processors for personal computers forecast third-quarter sales that exceeded analysts' estimates, citing new chip orders.SanDisk Corp. added 9.6 percent to $45.57 as the maker of flash-memory cards also reported per-share earnings for the second quarter that topped estimates.Caterpillar, which accounted for the second-biggest proportion of the Dow at the start of trading, fell 5.8 percent to $105.15. The world's largest maker of construction and mining equipment posted profit, excluding $204 million in costs related to the acquisition of Bucyrus International Inc., of $1.72 a share, trailing the $1.75 average of 20 analyst estimates compiled by Bloomberg.“Caterpillar’s clearly a bellwether,” said Robert Carey, chief investment officer at First Trust Portfolios LP, in a telephone interview. The Wheaton, Illinois-based firm oversees about $50 billion. “Given the overwhelming number of companies that have beat estimates, anybody that comes up short is not going to be treated well.”C.R. Bard declined 12 percent, the most since March 1993, to $99.58. The maker of medical devices such as catheters and drains forecast third-quarter adjusted earnings of no more than $1.61 a share, less than the average estimate of $1.62 a share by 20 analysts surveyed by Bloomberg.McDonald's Corp jumped 2.3 percent, the biggest gain in the Dow, to $88.56. The world's largest restaurant chain said second-quarter profit rose 15 percent, topping analysts' estimates, as more consumers dined out and McCafe beverages boosted sales.Skyworks Solutions Inc. jumped 19 percent, the second- biggest gain in the Russell 1000 Index behind AMD, to $26.98. The wireless semiconductor company forecast fourth-quarter revenue of $400 million, beating the average analyst estimate of $371.3 million.Industrial shares declined 1 percent collectively, the worst performance out of ten groups in the S&P 500.Telecommunication companies erased 0.5 percent, led by Verizon Communications Inc.Verizon Wireless, the wireless carrier that's co-owned by Verizon and Vodafone Group Plc, said today it activated 2.3 million Apple Inc. iPhones in the second quarter, trailing AT&T Inc.'s 3.6 million devices in the period.