Bloomberg reports US stocks today plunged the most since the 1987 crash taking out commodity-related securities and even so-called defensive retail names like Wal-Mart (WMT) and Costco (COST) which both lost 8%.  The S&P 500 dropped 90 points or 9% to 907. The Dow Industrials fell 733 points or 7.87% to 8577. Today’s performance wiped out almost all of the October 13th gains when stocks rallied the most in almost 80 years. Notable decliners include Morgan Stanley (MS) -16% Citigroup (C) -13% and Bank of America (BAC) -10%. In the energy sector Exxon-Mobil (XOM) dropped 14% while Chevron (CVX) slid 12.5%. As for ...