The Nikkei stock index plunged over 2 percent early Friday, hit by heavy selling of technology shares tracking falls in their U.S. counterparts, while a stronger yen weighed on exporters. In the first 15 minutes of trading, the 225-issue Nikkei Stock Average dropped 801.86 points, or 2.05 percent, from Thursday to 38,279.39. The broader Topix index was down 37.16 points, or 1.38 percent, at 2,658.35.