Core Viewpoint - The article discusses the challenges and considerations of identifying "mainline sectors" during a bull market, suggesting that broad-based indices may be a more pragmatic choice for most investors [4][6][18]. Group 1: Mainline Investment Temptation and Identification Challenges - In bull markets, mainline sectors often yield significant excess returns, with data showing that in 2020, the top three industry indices had returns of 190.96%, 138.41%, and 135.19%, while the CSI 300 index only rose by about 27.21% [6][7]. - The difficulty of accurately identifying mainline sectors beforehand is highlighted, as many investors may only realize what the mainline was after the market has moved [8][10]. Group 2: Real Obstacles in Mainline Identification - Three main obstacles to identifying mainline sectors are discussed: 1. Extreme internal differentiation within industries complicates stock selection, as seen in the 2025 market where the ground equipment sector had a 103.73% annual increase, but individual stocks within the sector varied significantly in performance [10]. 2. The acceleration of valuation bubbles poses greater risks than broad indices, as high valuations can lead to significant corrections if industry progress does not meet expectations [10][11]. 3. Behavioral biases can interfere with investment discipline, leading to premature profit-taking or overconfidence, which can result in substantial losses [11]. Group 3: Unique Value of Broad-Based Indices - Broad-based indices offer unique advantages in risk diversification, stable returns, and operational convenience. They provide a better risk-return ratio through cross-industry and cross-market capitalization allocation [12][13]. - Historical data shows that broad-based indices like the CSI 300 had significantly lower maximum drawdowns compared to industry indices during bull and bear markets [13][15]. - The operational convenience of broad-based indices is enhanced by a well-established ecosystem of investment tools, such as ETFs, which lower the barriers for non-professional investors [16]. Group 4: Conclusion and Strategy - The article concludes that while broad-based indices may not outperform leading mainline sectors, they are often a better choice for ordinary investors due to their ability to mitigate emotional trading and provide stable returns [18][19]. - A suggested investment strategy for ordinary investors is the "core-satellite" approach, allocating 60%-80% of the portfolio to broad-based ETFs to capture market beta, while using 20%-40% for selective participation in mainline sectors to manage risk exposure [19].

Group 1 - The core viewpoint is that the bull market is ongoing, but it is essential to focus on the main line of investment to avoid poor performance [5] - The market rhythm is becoming faster, suggesting an adjustment of the RSR parameters for better alignment with current market conditions [5] - The article emphasizes the importance of understanding market trends and having a broad perspective, rather than relying on formulas for buying points [2][3] Group 2 - The "Lonely Three Styles" and the "Four Major Laws of the Main Line" are mentioned as frameworks for understanding market dynamics [3] - A strong continuation pattern is observed in the market, indicating a potential bullish trend [3] - The article suggests that the market's current state aligns with the author's initial expectations for a strong market continuation [3]