Zhi Tong Cai Jing·2026-01-05 00:12Core Viewpoint - The ongoing rise of AI-driven trading has led to new highs in the U.S. stock market, raising concerns about a potential financial bubble, but historical context suggests the situation is more complex than it appears [1][2]. Group 1: Market Performance - The S&P 500 index rose by 16% in 2025, with significant contributions from AI leaders like Nvidia, Alphabet, Broadcom, and Microsoft [1]. - Since the end of 2022, the S&P 500 index has increased by 79%, while the Nasdaq 100 index has surged by 130% [3]. Group 2: Investment and Spending - Major tech companies, including Microsoft, Alphabet, Amazon, and Meta Platforms, are projected to increase capital expenditures by 34% to approximately $440 billion over the next year [1]. - OpenAI has committed to investing over $1 trillion in AI infrastructure, a staggering amount for a non-public company that has yet to turn a profit [1]. Group 3: Historical Context and Comparisons - Historical analysis shows that past market bubbles have lasted an average of just over two and a half years, with peak gains averaging 244% [2]. - The current AI-driven market rally has already entered its third year, raising questions about its sustainability compared to previous market bubbles [3]. Group 4: Concentration of Stocks - The top 10 stocks in the S&P 500 now account for about 40% of the index, a level of concentration not seen since the 1960s [5]. - Historical precedents exist for high concentration levels, as seen in the 1930s and 1960s, but current levels are still a cause for concern among investors [5]. Group 5: Fundamentals and Valuation - Current AI giants have lower debt-to-earnings ratios compared to companies during the internet bubble, indicating stronger fundamentals [8]. - The S&P 500 index's valuation is at its highest level since the early 2000s, based on the cyclically adjusted price-to-earnings ratio [12]. - Despite rising valuations, some investors argue that the growth rates of tech stocks are not as inflated as during the internet bubble, with Nvidia's P/E ratio below 50 compared to Cisco's over 200 at its peak [15]. Group 6: Investor Sentiment and Risks - A recent survey indicated that investors view the AI bubble as the largest "tail risk" event, with over half of respondents considering the "seven major tech stocks" as the most crowded trade on Wall Street [18]. - Concerns are growing regarding whether the investments in AI will yield adequate returns, especially in light of increasing debt issuance [18].