US STOCKS SNAPSHOT-Wall St opens lower after Moody's rating cut; yields rise

May 19 (Reuters) - Wall Street's main indexes opened lower on Monday as Treasury yields rose after Moody's downgraded the U.S. sovereign rating, sharpening focus on its mounting debt.

The Dow Jones Industrial Average .DJI fell 111.9 points, or 0.26%, at the open to 42542.81. The S&P 500 .SPX fell 55.5 points, or 0.93%, at the open to 5902.88​, while the Nasdaq Composite .IXIC dropped 273.7 points, or 1.42%, to 18937.417 at the opening bell.