恐惧与贪婪齐舞！AI狂潮下，美股明年注定“坐立难安”

Group 1 - The core viewpoint of the articles is that the U.S. stock market is expected to experience significant volatility in 2026, driven by investor fears of missing out on AI-related gains while also worrying about a potential bubble burst [2][3][4] - The past 18 months have been characterized by significant sell-offs and rapid reversals, a trend likely to continue until 2026, with some strategists predicting that the AI boom will follow historical cycles of boom and bust [2][3] - Technology companies at the center of the AI investment boom have a substantial impact on the market, with their performance potentially offsetting declines in other sectors, thereby influencing the realized volatility of the S&P 500 [2][4] Group 2 - Strategists anticipate that stock volatility will be supported in 2026 due to the instability often associated with asset bubbles, predicting occasional declines exceeding 10% but also record rapid rebounds as traders realize the bubble has not burst [3][4] - UBS strategists emphasize that the question of whether the AI boom will continue or collapse makes holding contracts that increase volatility in the Nasdaq 100 index crucial for betting on both scenarios [3][4] - The VIX index is expected to maintain a median around 16 to 17 in 2026, but it could spike significantly during risk-off periods, influenced by both technical and macroeconomic factors [4][5] Group 3 - The popularity of dispersion trading, which bets on individual stock volatility rising while index volatility remains low, is expected to increase, with some funds taking contrary positions due to overcrowding in this strategy [5][6] - A fundamental volatility mechanism model proposed by strategists suggests dynamic switching between long and short volatility trades, indicating that a flattening yield curve signals buying volatility [6] - Overall, the low leverage in the U.S. corporate sector is seen as a precursor to a new AI-driven re-leveraging cycle, which could lead to higher credit spreads and stock volatility [6]