Tokyo stocks plunged on Wednesday, driving a key index down more than 6 percent, on concern that the US Federal Reserve will soon reduce economic stimulus and the yen\'s appreciation. The 225-issue Nikkei Stock Average on the Tokyo Stock Exchange (TSE) lost 576.12 points, or 4.00 percent, from Tuesday to 13,824.94, marking the fourth biggest loss this year. The broader Tokyo Stock Price Index, which includes all shares on the market\'s first section, was down 38.40 points, or 3.22 percent, to 1,155.26, with all 33 subindexes closing in negative territory. Federal Reserve Bank of Chicago President Charles Evans said Tuesday that the Fed could begin to scale back its 85 billion-a-month bond-buying program at its September policy meeting, prompting the Dow Jones Industrial Average to hit its largest fall since June. The yen\'s strength against the dollar also prompted Japanese investors to sell export-oriented issues. In the currency markets, at 3:40 p.m. (0640 GMT), the US dollar traded at JPY 97.09-12 versus JPY 97.70-80 in New York and JPY 98.36-37 yen in Tokyo at 5 p.m. Tuesday.