Key takeaways Semiconductor stocks erase $1.64 trillion in market value Nvidia, AMD and Micron face mounting selling pressure AI spending concerns outweigh strong chipmaker earnings US semico
US semiconductor stocks have lost approximately $1.64 trillion in market value over six trading sessions, as concerns about artificial intelligence spending, corporate debt and higher interest rates trigger one of the industry's sharpest selloffs of 2026.
The Philadelphia Semiconductor Index fell another 3.3% during October 15 trading, putting the sector on course for nearly $2 trillion in cumulative losses if the decline continued. Nvidia, AMD and Micron were among the major companies facing renewed pressure.
According to Reuters, investors are reassessing the enormous cost of developing AI infrastructure even as semiconductor manufacturers continue reporting strong demand.
Semiconductor Stocks Lose $1.64 Trillion in Six SessionsThe Philadelphia Semiconductor Index has fallen approximately 12% during its recent losing streak, reflecting a broad withdrawal from companies that benefited from the AI investment boom.
The selloff extends across chip designers, memory manufacturers and semiconductor equipment suppliers, suggesting investors are questioning valuations throughout the industry's supply chain.
Arm Holdings declined approximately 21% over the six-session period, while Applied Materials fell 16% and Intel lost 13%, according to market data cited by Bloomberg.
Company Six-Session Decline Arm Holdings −21% Applied Materials −16% Intel −13% Philadelphia Semiconductor Index Approximately −12%Figures reflect the six-session period reported on October 15. Individual stock moves may differ from subsequent trading.
AMD separately dropped 5.7% on October 14, marking its biggest one-day percentage decline since August 5.
The pressure follows a broader AI chip selloff that affected ASML despite its strong quarterly earnings and continued demand for advanced manufacturing equipment.
Meanwhile, the iShares Semiconductor ETF (SOXX) was heading toward an eighth consecutive daily decline, potentially its longest losing streak in approximately 11 years.
AI Spending and Debt Concerns Trigger Semiconductor SelloffThe downturn reflects growing uncertainty over whether AI infrastructure spending can generate sufficient financial returns to justify its enormous cost.
Major technology companies are investing hundreds of billions of dollars in computing capacity, but data center developers often rely on substantial borrowing to finance construction and equipment purchases.
The financial strain has become increasingly visible in CoreWeave debt, where five-year credit default swap spreads exceeded 1,000 basis points as investors demanded greater compensation for credit risk.
Higher borrowing costs could eventually affect chipmakers if their largest customers delay infrastructure projects or reduce planned equipment purchases.
September's US inflation report added another concern. Consumer prices rose 3.7% annually, increasing expectations that the Federal Reserve could maintain restrictive monetary policy or raise rates again.
Competition is also intensifying. Reports of technological progress at Chinese memory manufacturer CXMT have pressured memory-related companies, including Micron and other chip suppliers.
TSMC Earnings Show AI Demand Has Not DisappearedDespite the selloff, semiconductor companies continue reporting substantial revenue and profit growth.
TSMC's quarterly earnings showed a 69% increase in net profit, while the manufacturer forecast fourth-quarter revenue of $52.3 billion to $54.3 billion.
That performance suggests demand for advanced computing remains strong, even as investors become more skeptical about the industry's long-term profitability.
The distinction is particularly important for AI infrastructure stocks, where contracted revenue and operating growth do not necessarily translate into positive cash flow after financing costs.
A company can continue increasing earnings while its share price declines if investors reduce the valuation multiple they are willing to pay.
For now, the semiconductor selloff reflects a repricing of AI growth expectations rather than clear evidence of collapsing chip demand.
Upcoming earnings from major cloud providers and chipmakers will help determine whether spending remains strong enough to support the industry's elevated valuations.
