The Nasdaq Composite Index notched its biggest one-day slide in nearly 2½ years, dragging the broader market sharply lower, as investors resumed selling risky biotechnology and smaller technology stocks. While the S&P 500 and Dow Jones Industrial Average remain not far from record highs even after Thursday’s declines, the bottom has fallen out in shares of biotech, high-growth technology and Internet companies including Facebook FB -5.21% and Netflix,NFLX -5.18% which were some of the biggest winners in the bull-market rally. Many hedge funds have been hit with steep losses in those shares in recent weeks, as have traditional mutual funds  have been hit with steep losses in those shares in recent weeks, as have traditional mutual funds that own so-called growth and momentum stocks. On Thursday, biotech and high-tech stocks tumbled anew after a two-session reprieve. The Nasdaq Biotechnology Index slumped 5.6% on Thursday, while the Nasdaq Internet Index fell 4.6%. The broader Nasdaq index lost Nasdaq 129.79 points, or 3.1%, to 4054.11. That marked its biggest drop since Nov. 9, 2011. Facebook and Netflix both declined 5.2% on Thursday. “There’s been a lot of selling in these highfliers; anything with the huge [valuations] is really getting hit,” said Dave Rovelli, managing director of equity trading at brokerage Canaccord Genuity. More