Goldman Sachs' ex-AI index (SPXXAI) gained 6.7% over the past six months to 3,123.24, lagging the broader S&P 500, which rose 18.3% to 7,818.93 over the same period—revealing an 11.6 percentage point rally gap driven almost entirely by artificial intelligence stocks.
AI Enablers Drive Benchmark Record Highs
Goldman Sachs launched the SPXXAI index in February so institutional clients could hedge AI exposure, excluding approximately 45% of the S&P 500 market capitalization at launch. While both the S&P 500 and Nasdaq Composite achieved record closes on Tuesday, the ex-AI benchmark peaked back in August and currently sits 6.4% below its 52-week high of 3,337.19. In contrast, the standard S&P 500 trades just 0.3% under its record level, illustrating how non-AI equities have muted gains while broader markets move higher, similar to periods where Bitcoin lags behind record stock market highs.
Recent strength in the benchmark index was powered primarily by semiconductor and design companies. According to CNBC reporting, AMD, Marvell, Synopsys, and Cadence Design Systems each surged 20% or more over approximately 20 trading days. However, underlying market breadth remains soft across non-tech sectors; Schwab strategist Kevin Gordon noted that the average individual stock has fallen 14% peak-to-trough since early August.
Energy Stocks and the 'AI 2.0' Trade
Market observers are turning their focus toward power producers as a potential second phase of artificial intelligence infrastructure growth. Jan van Eck, CEO of asset manager VanEck, characterized semiconductor chips as the first stage of the sector's expansion, identifying power suppliers and nuclear energy as the upcoming "AI 2.0 trade."
- S&P 500 vs. Ex-AI: 18.3% six-month gain vs. 6.7% for SPXXAI (an 11.6% gap).
- Chip Stock Surge: AMD, Marvell, Synopsys, and Cadence Design Systems gained 20%+ in ~20 trading sessions.
- Constellation Energy Jump: Constellation Energy stock climbed 12.3% on Tuesday following a power agreement with Alphabet.
- Nuclear Approval Odds: Prediction market pricing cited by VanEck puts the probability of an approved nuclear plant this year below 10%.
The energy group has lagged earlier this year amid political concerns surrounding data center expansion. However, Constellation Energy jumped 12.3% on Tuesday after signing a power agreement with Alphabet. While van Eck suggested the contract could mark a bottom for utility providers, he noted that prediction markets place the probability of an approved nuclear plant this year at under 10%. "I think when that happens this dry spell for the AI 2.0 trade will be over," van Eck stated to CNBC.
Why It Matters
The growing performance gap between the S&P 500 and SPXXAI highlights how heavily equity indices rely on a concentrated group of technology hardware providers. If third-quarter capital expenditure guidance from cloud hyperscalers decelerates, broader markets could face sharp downside pressure due to weak support from traditional sectors. Investors will be watching whether energy infrastructure contracts can broaden market breadth into real-world asset plays.
