高盛闭门会-首席策略师用长期视角看ai和美股，泡沫早期但还没破多元化的必要性

Investment Rating - The report indicates a cautious outlook on the U.S. stock market, predicting lower returns compared to other regions, particularly Europe and emerging markets [6][7]. Core Insights - The technology sector has shown profit growth that consistently outperforms other industries over the past 15 years, although current valuations are not at historical bubble levels [1][2]. - Global stock market returns are expected to average 7.7% annually over the next decade, with the U.S. projected at 6.5%, Europe at around 7%, Asia at 10%, and emerging markets at 11% [7][9]. - There is an optimistic outlook for Asia and China, with GDP forecasts being raised due to increased investment in export-driven models and capacity expansion [9][10]. - The European market is experiencing a shift with a potential influx of foreign investment and local capital returning, driven by a weaker dollar and relaxed fiscal constraints in Germany [5][6]. Summary by Sections Technology Sector - The technology sector's performance remains strong, with a 30% increase in 2025, but it is not yet in a bubble phase compared to the late 1990s [11]. - The concentration of market capitalization among the top five U.S. tech companies is significant, accounting for at least 15% of the global market [11]. Market Valuation - U.S. stock valuations are considered high, leading to expectations of lower long-term returns, while European stocks are relatively undervalued with potential for structural reforms [6][7]. - The valuation gap between U.S. and European markets is notable, with European stocks trading at a larger discount compared to their U.S. counterparts [2][4]. Investment Trends - Retail investor activity is significantly higher in the U.S., with over one-third of household assets invested in stocks, compared to only about 10% in Europe [12]. - The report highlights a trend of capital outflows from Europe over the past decade, but recent changes indicate a potential reversal with increased foreign interest [5][6].