The S&P 500 and Nasdaq composite both closed at record highs on Tuesday, with the S&P 500 crossing the 7,800 threshold for the first time. The advance was driven almost entirely by a small cluster of technology stocks tied to the artificial-intelligence buildout, while the broader market continued to struggle under the weight of elevated interest rates and geopolitical uncertainty.
Nvidia, the dominant supplier of AI data-center chips, rose 4.5% over the past week to an all-time high, according to the Wall Street Journal. Meta Platforms has gained roughly 24% since Aug. 13, when the index last set a closing record. The combined market capitalization of the so-called Magnificent Seven—Nvidia, Meta, Alphabet, Amazon, Microsoft, Apple and Tesla—closed at a record near $25 trillion, underscoring the concentration of market leadership.
Meanwhile, oil prices moved higher Wednesday as fresh Houthi attacks on Saudi Arabian airports in Jazan and Najran revived fears of supply disruptions from the Middle East. Brent crude for December delivery rose 0.93% to $101.52 a barrel, while U.S. West Texas Intermediate for November advanced 0.81% to $90.16 per barrel.
Breadth deteriorates
Despite the headline index gains, market participation remains narrow. Less than half of S&P 500 constituents closed above their 200-day moving average on Tuesday, according to Dow Jones Market Data, a figure that has been declining since August. The Russell 2000 small-cap index, the Dow Jones Industrial Average, and even the equal-weighted S&P 500 have all trailed the benchmark over the past month.
Healthcare, banks, consumer staples and blue-chip industrials are broadly lower. Ten-year Treasury yields, though slightly lower Tuesday, remain near their highest level in two decades, creating a headwind for most companies outside the largest tech players. “Higher interest rates and inflation are taking a toll on other stocks in the S&P 500,” said Dan Russo, chief investment officer at Potomac Fund Management, in comments reported by the Journal. “It's only the fortresslike balance sheets at the large-cap end of the spectrum that are propping the market up.”
Why tech holds up
The conventional logic is that AI hyperscalers—Alphabet, Amazon, Microsoft and Meta—carry relatively low debt and strong cash generation compared with most of the index, making them more resilient in a high-rate environment. That view is being tested as all four now spend tens of billions of dollars on AI infrastructure, lifting their debt loads. But investors, for now, appear unfazed.
The market's narrow leadership is not new, but its degree is. The gap between the index's largest winners and the rest has widened considerably heading into the fourth quarter of 2026. Warnings about a potential reversal are circulating at the institutional level. Temasek, Singapore's state investment firm, told the Milken Asia Summit this week that a reversal in the AI trade represents the biggest risk to global markets, with chief investment officer Rohit Sipahimalani noting that “AI is such a fast-changing environment that things could change quite easily,” according to CNBC.
Wednesday brings the release of minutes from the Federal Reserve's September meeting—the central bank's first rate hike since 2023—which may offer further clues on the rate path ahead. Advisors may also want to monitor SpaceX's index impact as its debut reshapes benchmark concentration.
SpaceX eyes $40 billion raise for Nvidia chips
In a separate development with implications for Nvidia's growth trajectory, Bloomberg reported that SpaceX is seeking to raise approximately $40 billion in new financing, with a significant portion earmarked for Nvidia chip purchases to expand its AI computing infrastructure. Elon Musk previously confirmed that SpaceX would rely exclusively on Nvidia's hardware for its AI data centers, targeting more than two gigawatts of computing capacity by end of 2026.
For financial advisors, the persistent AI-led rally raises questions about portfolio diversification and risk management, especially as gold's rally drivers persist despite its price surge, offering an alternative hedge. Meanwhile, the U.S. dropped to 24th in a Natixis retirement index as debt and inflation bite, highlighting broader economic strains. And direct indexing adoption has climbed to 83% among U.S. advisors, a trend that may gain traction as market concentration increases.
