‘Black Monday’ crash fears are intensifying ahead of Monday, October 19, as Wall Street reels from an AI-led sell-off, rising oil prices, and renewed inflation concerns.
The latest turmoil has heightened concerns about a broader stock market crash in 2026. On Friday, the Nasdaq Composite fell 2.19%, the S&P 500 lost 1.22%, and the Dow Jones Industrial Average declined 0.55%, according to Reuters.
The sell-off left the Nasdaq down more than 4% for the week, while the S&P 500 recorded its worst weekly performance since January. The Cboe Volatility Index (VIX), Wall Street’s main fear gauge, surged nearly 25% to 20.57, its highest level since late July.
The latest sell-off reflects mounting concerns about the sustainability of AI investments, higher energy costs, and the possibility that borrowing costs will remain elevated.
AI-linked stocks have come under particular pressure as investors question whether companies investing heavily in data centers can generate enough revenue to justify their spending.
CoreWeave (NASDAQ: CRWV) plunged 12% on Friday, extending its five-session losses to approximately 25%. The company’s bonds also sold off sharply, pushing yields above 15%. Broadcom (NASDAQ: AVGO) fell 3.6%, while the Philadelphia Semiconductor Index recorded another decline, extending its losing streak to eight sessions.
Why stock market plunged on Friday
The weakness has raised concerns about whether highly leveraged AI infrastructure companies can generate sufficient returns to service their debt, with further financing stress potentially spreading to credit markets and the broader economy.
Meanwhile, Brent crude climbed to approximately $109 a barrel amid Middle East tensions and supply disruption fears, raising inflation risks and potentially limiting the Federal Reserve’s ability to cut interest rates. Stronger-than-expected U.S. producer-price data has added to concerns about borrowing costs and pressure on growth-stock valuations.
Investor leverage presents another risk, as U.S. stock-market margin debt reached approximately $1.5 trillion before easing to $1.4 trillion in August, still 27% higher year over year. A prolonged sell-off could trigger margin calls, forcing investors to liquidate holdings and amplifying losses, although elevated debt alone does not signal an imminent crash.
Prediction markets remain unfazed
Despite mounting concerns, Polymarket assigned a 7% probability of an AI bubble burst by December 31, 2026, rising to 16% by June 30, 2027. The respective contracts recorded approximately $2.44 million and $26,906 in trading volume.
The market requires at least three specified events within 90 days to qualify, including a 50% drop in Nvidia (NASDAQ: NVDA) from its all-time high, a 40% decline in the iShares Semiconductor ETF from its peak, or certain major AI-company failures.
These odds reflect the likelihood of meeting specific criteria, not the probability of a broader stock-market crash or another Black Monday-style collapse.
Meanwhile, Polymarket’s October 19 S&P 500 opening contract showed a 44% chance of an upward opening, implying a 56% chance of opening lower. The contract reflects the expected direction at the open, not the potential size of a decline, and its odds may change as trading continues.