Stock market today: Dow, S&P 500, Nasdaq gains fizzle with AI buzz, Trump's shutdown threats in focus

Market Overview - US stocks exhibited mixed performance, with the Nasdaq Composite rising while the S&P 500 and Dow Jones Industrial Average both declined by 0.2% [1] - The S&P 500 reached a new all-time high, closing above 6,700 for the first time, driven by a decrease in ADP jobs numbers which reinforced expectations for interest-rate cuts [2] Technology Sector - OpenAI's valuation surged to $500 billion following an employee share sale, positioning it as the most valuable startup globally, surpassing SpaceX [3] - Positive sentiment in the AI sector contributed to a rally in chip stocks, with Nvidia achieving a record high, alongside gains for AMD and SK Hynix [2] Labor Market Insights - Private data indicated that hiring plans are at their lowest since 2009, despite a decrease in layoffs, suggesting a softening labor market [6] - The upcoming September jobs report is expected to be delayed, impacting market focus as Federal Reserve policymakers consider labor market conditions for their October rate decision [5][6]