This week’s market action reflected renewed caution amid evolving signals from the US Federal Reserve, with tech stocks facing pressure from shifting interest rate expectations and renewed overvaluation concerns.
Artificial intelligence (AI) heavyweight NVIDIA (NASDAQ:NVDA) announced a US$100 billion investment partnership with OpenAI on Monday (September 22), deploying at least 10 gigawatts of NVIDIA-powered data centers.
The initial US$10 billion investment will occur once the first gigawatt is operational in late 2026. OpenAI will purchase chips from NVIDIA with this investment, and NVIDIA will receive non-controlling equity in OpenAI.
The news was initially met with optimistic market sentiment, buoying NVIDIA shares and related AI-focused tech stocks.
Similarly, data center developers experienced a surge in their stock prices due to the increasing need for AI infrastructure. This was further fueled by announcements of significant expansion projects, such as the Stargate initiative. This rally hasn’t translated to ongoing price momentum at this point.
Global markets gained ahead of Fed Chair Jerome Powell’s Tuesday (September 23) remarks, in Providence, Rhode Island, during which he offered cautious guidance and dimmed hopes for near-term rate cuts.
Meanwhile, Canada’s S&P/TSX Composite Index (INDEXTSI:OSPTX) marked a milestone, breaking 30,000.
The milestone came as Bank of Canada Governor Tiff Macklem stressed the urgent need for economic reforms to counteract risks from US trade protectionism and the US dollar’s declining safe-haven status.
A more cautious tone emerged midweek, with analysts and investors weighing potential risks around the scale of the deal, including concerns about circular financing and renewed questions about market concentration.
Oracle’s (NYSE:ORCL) issuance of US$18 billion in public debt to expand its AI data center operations fueled concerns about escalating leverage risks. Meanwhile, at the macro leve, factors such as stronger-than-expected US unemployment numbers, and geopolitical tension after US President Donald Trump’s contentious remarks at the UN General Assembly, contributed to a market pause. Major US indexes marked their third straight day of losses on Thursday (September 25), with the tech sector bearing much of the brunt.
Nasdaq-100 performance, September 19 to 26, 2025.
Chart via Nasdaq.
The market rebounded slightly on Friday (September 26) as the latest US personal consumption expenditures index data aligned with expectations, giving investors relief and a sense of continued stability.
The Nasdaq-100 (INDEXNASDAQ:NDX) and S&P 500 (INDEXSP:.INX) posted modest losses for the week, reflecting a wait-and-see mood heading into the fourth quarter.
Apple, Global Foundries and Intel performance, September 23 to 26, 2025.
Chart via Google Finance.
Gains across AI-focused exchange-traded funds (ETFs) this week reflected ongoing investor optimism for AI innovation and infrastructure buildup. The VanEck Semiconductor ETF (NASDAQ:SMH) led the pack with a 1.74 percent increase, followed by the Invesco PHLX Semiconductor ETF (NASDAQ:SOXQ), which gained 0.85 percent, and the iShares Semiconductor ETF (NASDAQ:SOXX), which advanced by 0.82 percent.
Securities Disclosure: I, Meagen Seatter, hold no direct investment interest in any company mentioned in this article.