Stock Market Midday, Oct. 15: Markets Mixed as AI Sell-Off Continues

Markets split on October 15, 2026, as an AI-financing scare hit semiconductors: the Dow rose 0.82% while the Nasdaq fell 0.36%.

The catalyst was a pair of worries over AI debt and capital costs. CoreWeave (CRWV) bond yields at 15% spooked investors, and inflation data added pressure on the same session. A 15% borrowing cost for a leading AI infrastructure name puts a number on how expensive it has become to fund the buildout.

NVDA's CEO tried to restore confidence, but the semiconductor sell-off continued through midday. The index split points to rotation rather than broad risk-off: the Dow's gain alongside the Nasdaq's decline suggests money moving away from tech-heavy AI exposure.

The stakes are large. AI stocks make up 40% of the S&P 500, so stress in AI financing can reach well beyond chip names. Interpretation: that concentration means a funding scare in one corner of the AI trade can drag on index-level performance, which is why the story is macro rather than isolated to NVDA or CRWV.