By Benjamin Pimentel, MarketWatch SAN FRANCISCO (MarketWatch) -- Technology stocks were mostly in the red Thursday, as shares of Akamai Technologies Inc. tumbled after the Internet software and services company issued a muted forecast. Akamai (AKAM) fell more than 14%, the leading decliner on the S&P 500 Index. The Nasdaq Composite Index (RIXF) slipped a fraction to 2,866. However, the S&P 500 (SPX) was up a fraction, thanks to gains in shares of Citrix Systems Inc. (CTXS) which jumped more than 8% after the information-technology-services company reported upbeat results. Citrix was the S&P 500's top gainer. "Guidance appears conservative and we see upside to estimates in the second half of 2011," said Lazard Capital Markets analyst Joel Fishbein said in a note. "Customer activity and pipeline are at record levels, and Citrix continues to have good momentum on the back of strong execution." The Morgan Stanley High Tech 35 Index (MSH) was down 0.6%, while the Philadelphia Semiconductor Index (SOX) slid 1%. The tech sector also took a hit from shares of Teradyne Inc. (TER), which were down more than 14% a day after the electronic production equipment maker reported a jump in quarterly profit, but issued a weaker-than-expected forecast.