U.S. stocks opened mixed on Sept. 29, with the S&P 500 and Nasdaq Composite advancing as oil prices pulled back. Media reports detailing Anthropic’s public offering supported sentiment toward technology stocks. The Dow Jones Industrial Average fell 64.6 points, or 0.13%, to 51,416.96 at the open, while the S&P 500 rose 15.9 points, or 0.21%, to 7,699.6. The Nasdaq Composite gained 84.22 points, or 0.31%, to 26,904.60.