指数百分位，使用的时候要注意这四点｜投资小知识

Core Viewpoint - The article discusses the importance of historical data in understanding market cycles and the impact of index rule changes on valuation metrics. Group 1: Historical Data Reference - Historical market cycles typically last 7-10 years, making it essential to consider longer time frames rather than just 2-3 years to avoid incomplete analysis [2]. - It is recommended to find similar style indices with longer histories for reference, as they tend to exhibit similar performance patterns during different market phases [3]. Group 2: Index Rule Changes - Changes in index rules can lead to significant valuation shifts, making historical valuation data less relevant [5]. - For example, the change of the CSI 100 index name to CSI A100 altered its selection criteria from market capitalization to a leading stock strategy, affecting its valuation [5]. - The H-share index's transition from 40 to 50 stocks, including more internet companies, also resulted in a loss of reference value for historical valuations [6]. Group 3: Valuation Calculation Methods - Different weighting algorithms in index valuation can lead to changes in percentile rankings, impacting the perceived valuation metrics [6]. - The CSI Dividend Index's shift from market capitalization weighting to dividend yield weighting significantly altered its composition, affecting its valuation calculations [8][9]. Group 4: Economic Downturns - During economic downturns, declining profits can lead to an increase in price-to-earnings (P/E) ratios, which may not reflect actual stock price increases [11][13]. - For instance, small-cap indices like CSI 1000 and CSI 2000 have experienced profit declines over the past two years, necessitating the use of stable financial metrics for valuation [14]. - In cases of unstable or declining profits, the price-to-book (P/B) ratio may serve as a more reliable valuation metric [15].