For most of this year the question about artificial intelligence on Wall Street was how much revenue it would eventually produce. In the week that ended on Friday, October 16, 2026, the question changed: who is carrying the debt that paid for it, and at what rate.
The Nasdaq Composite fell 2.14% on Friday to 26,140.03, down nearly 5% over the five sessions — its worst week since June, and the end of a four-week winning streak. The S&P 500 lost 1.09% on the day, to 7,659.44, and more than 2% on the week. The Dow Jones Industrial Average, lighter on technology, slipped 175.28 points, or 0.34%, to 52,002.41, and still finished the week up 0.7%.
Both the S&P 500 and the Nasdaq closed below their 50-day moving averages. The Cboe Volatility Index, the market's standard measure of expected turbulence, jumped about 30% on Friday and rose above 22 for the first time in four months. Both indexes had set record highs roughly ten days earlier.
One company carried the argument
CoreWeave, which rents out computing capacity for AI development and counts Nvidia among its backers, fell between 12% and 14% on Friday — the figure varies with the tally — and shed about a quarter of its value over the week. It trades more than 60% below the peak it reached shortly after its March 2025 initial public offering.
The number investors keep returning to is its borrowing: CoreWeave's total debt has passed $51 billion. Gil Luria, head of technology research at D.A. Davidson, told CNN that the doubt is not whether demand for AI is real — he said it is real and growing — but whether a company expanding at this speed, with financing costs rising alongside bond yields, can earn enough to repay what it owes. Michael Rosen, of Angeles, took the other side, telling reporters that rising debt issuance deserves watching but that the market is not near excessive levels.
The shares had briefly risen on Thursday after Nvidia chief executive Jensen Huang spoke favorably about the company to Bloomberg. The gain lasted a day.
The chip trade turns
CrowdStrike fell 7% on Friday and Oracle 4.5%. The VanEck Semiconductor ETF dropped 3% on the day and 10% on the week, its steepest weekly fall since April 2025, with Micron, AMD and Sandisk leading the decline. A separate, closely watched chip index fell 3.9% on Friday, its eighth consecutive daily loss; it is now more than 20% below its June peak while still up nearly 60% for the year — a reminder of how far the sector had run before this month.
That gap matters beyond the sector. Semiconductors account for roughly one-fifth of the S&P 500's market value, so a chip correction is not a sector story for long.
The repricing was not confined to the United States. South Korea's Kospi, heavy with SK Hynix and Samsung Electronics, fell 14.5% on the week, its worst since 2008 — and is still up about 35% for the year.
Oil and the Fed
Crude rose while equities fell, on tension between Washington and Tehran and on the war in Ukraine. WTI gained 3.51% to $101.41 a barrel and Brent 3.72% to $109.86.
Expensive energy and a jittery equity market arrive two weeks before the Federal Reserve's meeting on October 27 and 28. Pricing on the CME's FedWatch tool put the probability of no change in rates at that meeting at 82% — a market that expects the central bank to sit still while it works out what the week meant.
Reporting from CNN, NBC News, CNBC and CoinCentral.
