Aug 21 (Reuters) - Wall Street's main indexes opened lower on Thursday, as investors turned cautious ahead of the Federal Reserve's three-day conference in Jackson Hole, while big-box retailer Walmart's quarterly results did little to lift sentiment.
The Dow Jones Industrial Average .DJI fell 130.1 points, or 0.29%, at the open to 44,808.21. The S&P 500 .SPX dropped 14.9 points, or 0.23%, at the open to 6,380.83, while the Nasdaq Composite .IXIC declined 60.3 points, or 0.28%, to 21,112.523 at the opening bell.