Core Insights - The article discusses the resilience of the U.S. market over the past decades, highlighting the rapid recovery of the S&P 500 after downturns, such as a 30% drop during the COVID-19 pandemic, which was fully recovered within six months and ended the year up over 10% from the initial pandemic level [1]. Group 1: News as an Indicator - The potential of news to serve as an early indicator of U.S. bear markets is explored, emphasizing the cyclical nature of news and its impact on stock behavior [1]. - LSEG's research indicates that while company-specific news may be sparse, the overall sentiment in U.S. market news exhibits high autocorrelation over longer lag periods, posing challenges for predicting market shifts [2]. - To effectively utilize news sentiment as an indicator, adjustments are necessary to account for observed autocorrelation, suggesting a five-day smoothing approach to enhance robustness [7]. Group 2: Market Sentiment Analysis - The article presents a method for calculating daily overall news sentiment by aggregating sentiment scores from articles related to U.S. listed stocks, which is crucial for predicting significant market changes [5]. - Historical analysis shows that sustained negative sentiment signals preceded notable market declines in recent bear markets, indicating the effectiveness of sentiment analysis in forecasting market trends [7]. Group 3: Investor Behavior - Investors in the U.S. market typically operate in bullish environments, which influences their trading strategies, whether systematic or discretionary [11]. - Utilizing news as an early warning system for potential market shifts can help investors maintain flexibility and adapt their strategies accordingly [11].

这里的目标则是利用新闻来预测更广泛的市场趋势。从这一角度来看，新闻一点也不稀疏。每天交易 日都会产生并记录数以万计的文章。然而，当我们从关注具体公司新闻转向对美国市场整体进行聚合 时，一个新的问题出现了。 我们发现，稀疏性的挑战被序列相关性所取代。 正如图1所示，美国每日 整体新闻情绪在相对较长的滞后期内都表现出高度的自相关性。 图1：美国每日整体新闻情绪的滞后自相关 每日整体数据通过对所有与美国上市股票相关的文章的情绪评分进行求和来计算。 这似乎对我们既 定的目标提出了真正的挑战——利用整体新闻信号来预测美国市场的剧烈变化。要实现这一点，我 们需要一个尽可能接近"无记忆"的指标。这样的指标才更有可能及时感知市场的转折。 Amit Das LSEG 新闻数据与API业务 在过去几十年里，美国展现出极强的增长韧性，期间伴随少数几次急剧的熊市。然而，总体趋势保持 积极，熊市后的复苏通常也很迅速。我们可以用S&P500来说明这一点。在COVID-19疫情初期的冲 击下，S&P500市值下跌约30%。然而，仅一个月后它便开始稳步回升。在六个月内，它完全收复了 失地。到年底时，指数较疫情初始已上涨超过10%。 在本篇洞 ...