Nikkei opened 1.96 percent lower Thursday morning on sluggish U.S. economic performance. At 9:15 a.m., the 225-issue Nikkei Stock Average lost 242.10 points, or 1.96 percent, from Wednesday to 12,120.10. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was down 16.13 points, or 1.60 percent, to 994.30.