Nikkei opened 0.86 percent lower Friday as sentiment was dented by fresh concern over the U.S. economy following weak economic data. At 9:15 a.m., the 225-issue Nikkei Stock Average fell 129.96 points, or 0.86 percent, from Thursday to 14,907.28. The broader Topix index of all First Section issues on the Tokyo Stock Exchange was down 7.39 points, or 0.59 percent, to 1, 237.84.