The Nasdaq Composite surged to a record-high close on September 22, driven primarily by gains in AI-related semiconductor stocks, while the S&P 500 ended just shy of its own record high amid volatile oil prices hovering around $100 per barrel.
Micron Technology led the chip sector with a 5% increase, and Sandisk climbed nearly 7%. These gains came as investors responded positively to the recent launch of Meta Platforms’ AI assistant, Muse, which is capable of performing tasks such as sending emails and completing transactions on behalf of users. The assistant’s early adoption has bolstered stock prices among companies involved in artificial intelligence technology.
Despite the enthusiasm for AI advancements, some market participants expressed concerns about the potential disruptive impact of AI assistants on various consumer sectors. Amazon blocked Muse from making purchases on its platform starting September 21, reflecting worries over competitive threats AI might pose to retailers, online brokerages, and other consumer-focused businesses. This anxiety was reflected in share price declines among companies including Uber Technologies and Lyft, which both fell more than 1%, Charles Schwab, which dropped 6.1%, and Airbnb, down 3%.
Oil prices fluctuated near the $100 mark amid ongoing geopolitical tensions. The benchmark 10-year U.S. Treasury yield remained around 4.94% following remarks by President Donald Trump at the United Nations General Assembly. Trump warned of potential severe military action against Iran if no agreement is reached to resolve Middle East conflicts.
Market participants also turned their attention to a scheduled U.S.-China summit on September 24. Traders anticipated that discussions might lead to an extension of the trade truce between the two countries and possibly address regulatory frameworks for artificial intelligence. Joe Saluzzi, head of equity market structure research at Themis Trading, noted that investors are hopeful the talks could signal the beginning of a cooperative approach to global AI governance rather than continued rivalry.
The S&P 500 closed essentially flat at 3,764.64 points, less than 0.5% below its all-time closing high set on August 13. The Nasdaq Composite rose 0.45% to close at 13,244.28 points, marking its second consecutive record close. Meanwhile, the Dow Jones Industrial Average retreated 0.36% to 33,863.69 points.
Trading volume was robust, with approximately 17.9 billion shares exchanged on U.S. markets, surpassing the 20-day average of 16.3 billion. Sector performance was mixed: six of 11 S&P 500 sectors posted losses, led by a 1.68% decline in financials and a 0.8% drop in communication services. Major financial institutions such as JPMorgan Chase and Wells Fargo both declined by more than 3%.
In monetary policy developments, Boston Federal Reserve President Susan Collins expressed support for the Federal Reserve’s recent interest rate hike, citing persistent inflation risks. New York Fed President John Williams commented positively on the Fed’s management of short-term rates to stabilize markets. The CME Group’s FedWatch Tool indicated a roughly 53% probability that the Fed will raise interest rates by at least 25 basis points in October.
Among individual stocks in the S&P 500, the number of advancing and declining issues were roughly equal. The S&P 500 recorded nine new highs and 16 new lows, while the Nasdaq posted 48 new highs and 110 new lows.