(Bloomberg) -- Japan Exchange Group Inc., operator of the Tokyo Stock Exchange, is having a year to forget, with its stock falling about 40 percent and trailing the almost 7 percent gain of the BI Global Security & Commodity Exchanges Valuation Peer Group. Japan’s benchmark Topix index is down close to 20 percent this year, while average daily share turnover has declined more than 7 percent. The stock’s plunge is the biggest among all listed exchange companies, ahead of Euronext NV’s 30 percent drop.To contact the reporter on this story: Sam Mamudi in Hong Kong at smamudi@bloomberg.net. To contact the editors responsible for this story: Jeff Sutherland at jsutherlan13@bloomberg.net.