Stocks extended their advance heading into the last hour of the regular session, with the indexes poised to cap the holiday-shortened week with gains. The Dow Jones industrial average powered ahead 0.7%, while the Nasdaq and S&P 500 were up 0.4% each. Volume in the stock market today remained higher across the board vs. this time Thursday. The Nasdaq is now less than 4% below its March 2000 peak as it climbs toward an all-time high.