(Reuters) - Wall Street's main indexes were flat at the open on Wednesday ahead of Nvidia's earnings report, with focus squarely on whether the recent bull market rally led by the AI chip firm and other tech-related shares can be sustained.

The Dow Jones Industrial Average fell 0.33 point, or flat, at the open to 41,250.17. The S&P 500 opened lower by 1.29 points, or 0.02%, at 5,624.51, while the Nasdaq Composite dropped 16.02 points, or 0.09%, to 17,738.80 at the opening bell.