The benchmark Nikkei stock index finished Wednesday at its highest closing level since December 1996, extending its winning streak for a seventh consecutive day.

This was owing to investor sentiment being bolstered by expectations for both domestic and overseas economic recoveries.

The 225-issue Nikkei Stock Average added 57.76 points, or 0.28 percent, from Tuesday to finish the day at 20,881.27.

The broader Topix index of all First Section issues on the Tokyo Stock Exchange, meanwhile, added 1.67 points, or 0.10 percent, to close at 1,696.81.

Insurance, nonferrous metal and land transportation-linked issues comprised those that gained the most by the close of play.