Wall Street closed out September 2025 on a high note on the 30th, with technology shares driving fresh records even as a federal government shutdown loomed just hours away. Nvidia shares closed at an all-time high, pushing the chipmaker's market capitalization past $4.5 trillion, while a blockbuster AI infrastructure deal lifted CoreWeave sharply, showing that the AI trade still had room to run even as Washington's funding standoff hung over the session and a deadline approached at the stroke of midnight.
Records Amid the Countdown
The S&P 500 rose 0.41% to close at 6,688.46, the Nasdaq Composite added 0.31% to finish at 22,660.01, and the Dow Jones Industrial Average climbed 81.82 points, or 0.18%, to 46,397.89, a fresh closing high for the blue-chip index. CoreWeave jumped roughly 12% after announcing a $14.2 billion deal to supply Meta with AI cloud infrastructure, one of the largest agreements of its kind to date, while Nvidia's advance to a record close underscored how central a small group of AI-linked names remained to the broader market's direction heading into the fourth quarter.
A Strong Close to a Strong Quarter
The rally capped a strong month and quarter for equities despite the shutdown backdrop. The S&P 500 gained more than 3% in September, defying a five-year seasonal average decline of 4.2% for the month, while the Nasdaq outperformed with a 5.6% monthly advance. For the third quarter as a whole, the S&P 500 rose almost 8% and the Nasdaq gained more than 11%, reflecting sustained investor conviction in AI infrastructure spending and a broader risk-on tone that persisted through the summer and into early autumn.
The Shutdown Clock Was Still Ticking
Even so, the shutdown risk was impossible to ignore. Federal funding was due to expire at midnight, and President Trump told reporters that a shutdown was "probably likely," even if "nothing is inevitable." Investors largely looked past the political brinkmanship, drawing on the historical pattern that past shutdowns had limited lasting market impact, with the S&P 500 having climbed an average of 4.4% during previous shutdown periods, even though this one would ultimately stretch into the longest in U.S. history, furlough roughly 750,000 federal workers, and delay key economic data releases, including the September jobs report, for weeks.
What It Means for Traders
For traders, the session showed how a powerful sector-specific narrative, in this case AI infrastructure spending, can override macro and political uncertainty in the short term, though that calm proved only partial once the shutdown actually began the next day and data delays started to cloud the broader economic outlook. Watching AI-linked megacaps as a bellwether for broader risk appetite, while separately tracking shutdown-related headlines and their implications for scheduled data releases like the September jobs report, remained essential for positioning through early October.
Daily market analysis by BCM Markets.