U.S. markets headed lower Wednesday morning after the National Association of Realtors said existing home sales fell from January to February. Following a mixed construction report issued Tuesday -- with housing starts down, but building permits up -- the NAR said Wednesday that sales fell 0.9 percent from January, but were up 8.8 percent from February 2011. In midmorning trading Wednesday, the Dow Jones industrial average lost 14.50 points, or 0.11 percent, to 13,155.69. The Standard & Poor\'s 500 index shed 1.92 points, or 0.14 percent, to 1,403.60. The tech-heavy Nasdaq composite index gave up 0.64 points, or 0.02 percent, to 3,073.51. The benchmark 10-year treasury rose 13/32 to yield 2.316 percent. The euro rose to $1.3248 from Tuesday\'s $1.3225. Against the yen, the dollar rose to 83.78 yen compared to Tuesday\'s 83.35 yen.