The Nikkei stock index ended down 2.7 percent Friday, hit by global economic concerns stemming from escalating conflict in the Middle East and semiconductor issues being dumped amid fears of a slowdown in growth in the industry. The 225-issue Nikkei Stock Average finished down 1,011.35 points, or 2.66 percent, from Thursday at 37,068.35. The broader Topix index ended 51.13 points, or 1.91 percent, lower at 2,626.32. On the top-tier Prime Market, decliners were led by electric appliance, machinery and metal product shares.