The Sensex at the Bombay Stock Exchange tumbled 467 points, or 2.8 per cent, to a three-month low of 16,408, on Wednesday, on panic selling by investors. The Nifty at the National Stock Exchange plunged 147 points, or 2.9 percent, to close below the 5,000 level, at 4,920. The domestic markets fell in-line with the sell-off in the global markets, after Germany banned speculators from some bets against government bonds and other securities, and German Chancellor Angela Merkel said the euro is at risk.Stock markets in Japan, China, Hong Kong, South Korea and Singapore shed between 0.3 percent and 2.5 percent. The European bourses lost about 2.5 percent.