Stocks fell sharply on Wall Street yesterday, extending a dismal week as investors became increasingly certain that the Federal Reserve would raise interest rates to slow down the robust US economy. While fears about a rate increase have shaken stocks for weeks, rumours that the Fed would boost rates higher or sooner than previously thought sent the market sliding in afternoon trading. At the close on Wall Street, the Dow Jones was down 130.76 points at 10,490.51. The blue-chip index fell 309.33 points, or 2.9 per cent for the week.