Trump’s Bull Market Is Standing on Shaky Legs. Just 5 Stocks Account for 52% of the S&P’s Gains

The S&P 500’s 22% rise since Donald Trump’s inauguration in January 2025 masks a critical imbalance: just five semiconductor stocks—Nvidia, Micron Technology, Broadcom, Advanced Micro Devices, and Intel—contributed 51.6% of the index’s gains. These companies, central to the AI boom, have surged due to massive corporate spending on AI infrastructure, with Microsoft, Amazon, Alphabet, and Meta projected to invest $725 billion in 2026 alone. The PHLX Semiconductor Index has climbed 68% this year, outpacing the S&P 500’s 8% gain, while semiconductor stocks now represent 23% of the index’s market cap. Nvidia alone added 110 points to the S&P 500’s 536-point year-to-date advance, reflecting concentrated demand for GPUs, memory, and AI accelerators. Yet this rally has left the remaining 495 S&P 500 companies accounting for just 48.4% of gains, signaling a narrow market driven by a single sector. Valuations reflect this speculative fervor: Nvidia trades at 19x forward earnings, Micron at 7x, Broadcom at 23x, AMD at 31x, and Intel at 71x. While AI demand remains robust, high concentration creates vulnerability—export restrictions, earnings misses, or guidance cuts could trigger sharp corrections. Unlike the dot-com boom, today’s rally occurs amid elevated interest rates, reducing room for error. The market’s fragility is further highlighted by the AI-driven bubble in chip stocks, which soared 70% in April. Investors are betting on sustained AI growth, but the lack of broad economic participation raises questions about the rally’s durability. If semiconductor leadership falters, the broader market could face significant downside pressure, undermining the perceived strength of Trump’s economic recovery.