Wall St opens lower as bank earnings disappoint; Dow slumps over 300 pts

Wall Street's main indexes opened lower on Thursday as downbeat earnings from big U.S. banks JPMorgan Chase & Co and Morgan Stanley underscored concerns about a sharp economic downturn caused by aggressive monetary policy tightening.

The Dow Jones Industrial Average .DJI fell 320.99 points, or 1.04%, at the open to 30,451.80.

The S&P 500 .SPX opened lower by 37.79 points, or 0.99%, at 3,763.99, while the Nasdaq Composite .IXIC dropped 96.37 points, or 0.86%, to 11,151.21 at the opening bell.