Expert Insights

U.S. stocks fell sharply Friday as selling in artificial-intelligence and semiconductor shares intensified, with investors increasingly questioning the debt-heavy financing behind the AI infrastructure boom as rising oil prices added another source of pressure.

The S&P 500 (SPX) fell 1.09%, the tech-heavy Nasdaq-100 (/NDX) dropped 2.5% and the Dow Jones Industrial Average ($DJI) declined 0.35%. The Russell 2000 (RUT) lost 1.66%.

Semiconductors remained at the center of the selloff, with the PHLX Semiconductor Sector Index (SOX) dropping 3.83%. The CBOE Volatility Index (VIX) surged nearly 21% to the closely-watched 20 level. The 10-year Treasury yield held near 5.10%, while the U.S. Dollar Index ($DXY) slipped 0.25% to 101.787. WTI crude climbed 2.6% to about $99 per barrel, helping the S&P 500 energy sector outperform as technology remained under heavy pressure.

It's been a rough week for the AI trade. Selling first picked up after reports that China's ChangXin Memory Technologies had made advances in memory-chip technology. That raised competitive concerns for global producers and helped drive steep weekly declines in shares of Micron (MU), Samsung Electronics and SK Hynix (SKHY).

Attention then turned to how the AI buildout is being financed, especially among so-called neocloud providers that lean heavily on outside capital and debt to fund GPU-intensive infrastructure. Both stocks and bonds sold off on growing concern that aggressive spending plans could become harder to sustain if borrowing costs stay high or if AI revenue growth doesn't keep up with investment.

Three things to watch from Friday’s market:

CoreWeave Extends Rout as Debt Concerns Intensify

A major rotation defined the week as investors moved away from AI trades and back toward defensive stocks and government bonds.

The Dow Jones Industrial Average ($DJI) and Dow Transports led the broader market over the past week, while the S&P 500 (SPX) slipped modestly, and the Nasdaq-100 (NDX), and Russell 2000 (RUT) lagged more noticeably. Thursday’s session initially extended the technology selloff before buyers stepped in, and falling Treasury yields helped stocks recover into the close.

Inflation remains an important catalyst. September CPI rose 0.6% month over month and 3.7% year over year, above expectations, with gasoline accounting for more than half of the monthly increase. Core CPI increased 0.3% and 2.6% year over year. Producer inflation was even hotter, up 1.3%, printing the largest monthly increase since 2022, while energy costs surged. Normally, that combination would pressure Treasuries, but bonds rallied instead in a move that may suggest some investors were weighing AI valuation and credit concerns alongside inflation risks.

This represents an important change in market behavior. For much of the year, enormous equity gains, government borrowing, and private-sector demand for capital associated with the AI infrastructure buildout coincided with heavy pressure on bonds. This week, traders increasingly crowded into Treasuries and out of AI mega-cap and infrastructure trades, restoring some of the bond market’s traditional safe-haven role. The shift came despite hot inflation, suggesting investors are becoming more concerned about whether highly leveraged AI infrastructure spending can generate adequate returns at today’s cost of capital.

Semiconductor Earnings Hit Records

Semiconductor earnings themselves remained impressive. ASML (ASML) reported record quarterly sales and said customer demand is strong enough that some clients are already discussing equipment needs for 2029 and 2030. Taiwan Semiconductor Manufacturing (TSM) reported record profit, with earnings jumping sharply as demand for leading-edge AI processors remained exceptionally strong. Yet both stocks struggled to sustain gains, demonstrating how elevated expectations can overwhelm strong quarterly results during a broader risk reset.