S&P 500 Halts Four-Day Slide: AI Chip Selloff Erases $1T as Healthcare Surges

The S&P 500 ended marginally lower on June 26, halting a four-day decline as investors rotated out of AI chip leaders and into defensive healthcare names. The benchmark index slipped 0.3% while the Nasdaq Composite fell 0.7%, pressured by a broad-based retreat in semiconductor stocks that wiped out more than $1 trillion in combined market capitalization across the sector.

What Happened

Nvidia falling 3.2%, Advanced Micro Devices dropping 4.1%, and Broadcom sliding 4.3%. ON Semiconductor plunged 23.7% after announcing an all-stock deal to acquire Synaptics, marking the largest single-day loss in the S&P 500. The VanEck Semiconductor ETF (SMH) tumbled 3.8%, extending a pullback that began after Micron Technology's earnings failed to sustain the AI-driven rally.

Meanwhile, Moderna surged 12.4% to lead the S&P 500, lifting the healthcare sector to a 1.8% gain — its best day in weeks. The sector rotation reflects growing investor skepticism about the near-term profitability of massive AI infrastructure spending, with OpenAI reportedly missing internal user and revenue targets. Broadcom's recent earnings disappointment, where management guided to slower AI revenue growth, amplified concerns that the chip boom may be peaking.

Why It Matters

The sector rotation signals a shift in market leadership after months of AI chip dominance. With the S&P 500's gains concentrated in a handful of mega-cap technology names, Friday's move suggests investors are diversifying into sectors with more immediate earnings visibility. Healthcare, utilities, and consumer staples — traditionally defensive areas — attracted inflows as the semiconductor selloff deepened. For global markets, the chip rout raises questions about the sustainability of the AI investment cycle that has driven equity returns since 2023.

What's Next

Traders will watch Nvidia's key support near $190 and the SMH ETF's 200-day moving average for signs of stabilization. Next week's economic calendar features the PCE inflation report and ISM manufacturing data, which could influence Federal Reserve rate expectations and further sector rotation. Earnings from remaining tech giants will test whether AI spending plans remain intact or if caution spreads beyond semiconductors.

August 2026 Update: S&P Reclaims 7,490, NVDA Back Above USD 200 — Rotation Still Running

The selloff did not become a crash. The S&P 500 ended July at 7,489.72 (July 31, +0.70%), recovering from a 1.52% Fed-day drop to 7,316 on July 29 when the central bank held rates steady (Reuters). Nvidia climbed back to USD 200.75 (+2.9% on July 31; +7.6% YTD), though it remains about 15% below its USD 236.54 52-week high.

Chips are wounded, not buried. The SMH ETF sat at USD 538.66 on July 30 (VanEck), still up 49.6% year-to-date but 13-20% below June highs as the "AI-valuation reset" grinds on. The OpenAI overhang grew: Yahoo/Futurism report it is on pace to miss its own ad-revenue forecast by 90%, and Morningstar now pegs a realistic IPO window at mid-to-late 2027 rather than Q4 2026.

The rotation thesis played out. WSJ declared the rotation trade "back" on July 2 after weak June jobs data, and Bloomberg's July 12 Taking Stock column put healthcare among the rotation's big winners — exactly the move this article flagged when Moderna led the June 26 session.

For context on recent chip market volatility, see our coverage of Nasdaq Falls Fourth Day: Apple Drop Overshadows Micron Blowout Earnings and the broader Sensex Nifty Rally: Banking Stocks Drive Indices to Record Highs. The Digital Asset Raises $355M: a16z Crypto Leads Round with HSBC, BNP Paribas, S&P Global Backing highlights institutional appetite amid the rotation. Historical parallels include the US Stock Market Loses $1 Trillion in Historic Chip Stock Crash and the SpaceX IPO 2026: $75 Billion Raise at $135 Per Share. Valuation concerns are explored in Shiller P/E Hits 42.66: Stock Market Valuation Nears Dot-Com Bubble Peak and the Nasdaq Plunge 4.2% analysis.