US STOCKS SNAPSHOT-Wall Street tumbles after big banks flag pullback risk

Nov 4 (Reuters) - Wall Street's main indexes tumbled on Tuesday as investors questioned lofty tech valuations after the CEOs of top Wall Street banks warned of a stock market selloff, while AI favorite Palantir's sales forecast failed to impress investors.

The Dow Jones Industrial Average .DJI fell 188.6 points, or 0.40%, at the open to 47,148.04. The S&P 500 .SPX fell 63.4 points, or 0.93%, at the open to 6,788.52​, while the Nasdaq Composite .IXIC dropped 376.5 points, or 1.58%, to 2,3458.211 at the opening bell.