And today in AI stock bubble-watching news… Quick insight: AI stock concentration has reached the same level that resulted in the bursting of previous bubbles, Bank of America strategists pointed out.
The “AI Big 10” now make up 41% of the S&P 500 (^GSPC), similar to the share of tech and telecom during the dot-com bubble
The 10 companies making up BofA’s AI Big 10 are Nvidia (NVDA), Microsoft (MSFT), Alphabet (GOOG, GOOGL), Amazon (AMZN), Meta (META), Apple (AAPL), Tesla (TSLA), Broadcom (AVGO), Micron (MU), and Advanced Micro Devices (AMD). The why: The Nasdaq Composite (^IXIC) delivered a blockbuster performance in the second quarter of 2026, surging 21.4% to post its best quarterly run since the post-pandemic rebound of 2020. The explosive growth was primarily fueled by an unrelenting investment boom surrounding artificial intelligence infrastructure.
That propelled semiconductor hardware heavyweights such as AMD and memory suppliers like Micron to record highs. Momentum in tech was further amplified by the mid-June IPO of Elon Musk’s SpaceX (SPCX). The tech-heavy index did experience a minor 2.8% pullback in June as investors briefly rotated capital into small caps and worried about Big Tech’s AI capital expenditures.