Wall Street had for the most part shrugged off a recent slide in global stock markets, viewing the declines as an adjustment that was bound to take place after so many years of uninterrupted gains. That complacent view was upended on Wednesday. Waves of nervous selling rocked the stock market in the United States, following an earlier sell-off in Europe. In midafternoon trading, the benchmark Standard & Poor’s 500-stock index was down 2.73 percent, wiping out its gain for the year. The Dow Jones industrial average was down 2.6 percent, leaving it down 4.5 percent for the year. All 10 sectors of the S.&P. 500 were ... (full story)