U.S. stocks rally to 15,994.77; Nasdaq positive for 2014 NEW YORK (MarketWatch) - U.S. stocks extended their four-day winning streak and ended Tuesday with solid gains as Federal Reserve Chairwoman Janet Yellen pledged to keep interest rates low and continue to taper the pace of bond purchases if the economy keeps improving. The Dow Jones Industrial Average briefly topped 16,000 and closed up 192.98 points, or 1.2% at 15,994.77. The 3.6% gain over the past four days was the best for four consecutive up days since June 8, 2012. The S&P 500 closed up 19.91 points, or 1.1% at 1,819.75, its best gain over four straight up days since Dec. 23, 2011. The Nasdaq Composite ended the day 42.87 points, or 1%, higher at 4,191.04. The tech-heavy index turned positive for 2014 and is now up 0.3% so far this year.