文 | 银行螺丝钉 （转载请注明出处） 投资指数基金时，百分位是一个很好的参考指标。 从低百分位的品种中，我们也可以尝试发掘出一些投资机会。 那么，在实际投资的时候，该如何参考这个指标呢？ 估值百分位的两种类型 百分位有两种： （1）时间百分位 是指当前估值在历史估值时间中，所处的百分位位置。 例如：最近5年，只有10%的时间里的估值，比当前更低，那当前的近5年百分位就是10%。 （2）空间百分位 是指当前估值，在历史最低到最高估值之间，所处的位置。 例如：最近5年，历史最低10倍市盈率，最高50倍市盈率。当前20倍市盈率，所处位置为25%。 通常来说，在实际投资中，时间百分位使用得相对多一些。 只看百分位投资，也会有风险 百分位是一个很好的参考指标。 从低百分位的品种中，可以尝试发掘出一些投资机会。 因为一个品种的估值，会长期围绕它的平均值上下波动。 如果估值过低或者过高，未来大概率会回归到均值附近。 不过，百分位只是一种辅助的判断指标。 在一些情况下，百分位也可能会失效。 只看百分位估值，有以下几种常见的风险： · 指数上线时间短，历史估值参考价值低。 · 指数规则修改，带来估值变化。 · 指数估值加权算 ...

Core Viewpoint - The article emphasizes the importance of percentile as a reference indicator when investing in index funds, suggesting that low percentile investments may present potential opportunities [1][6]. Summary by Sections Percentile Types - There are two types of percentiles: 1. **Time Percentile**: Indicates the current valuation's position within historical valuations over a specific time frame. For example, if the current valuation is lower than 90% of the valuations in the last five years, it is at the 10th percentile [3]. 2. **Space Percentile**: Represents the current valuation's position between the historical minimum and maximum valuations. For instance, if the historical minimum P/E ratio is 10 and the maximum is 50, a current P/E of 20 would place it at the 25th percentile [4]. Practical Investment Considerations - Time percentiles are more commonly used in actual investments, but relying solely on percentiles carries risks [5]. Risks of Relying Solely on Percentiles - **Risk 1**: Short index launch time can lead to low historical valuation reference value. For example, newly established indices may not provide a reliable bottom valuation due to limited historical data [9][10]. - **Risk 2**: Changes in index rules can significantly alter valuation data. For instance, the change in the China Securities 100 index from a market-cap-based selection to a leading strategy can affect historical valuation references [12][13]. - **Risk 3**: Different weighting algorithms for valuations can lead to changes in percentiles. For example, the China Securities Dividend Index's shift from market-cap weighting to dividend yield weighting has resulted in discrepancies in reported P/E ratios [14][18]. - **Risk 4**: Significant fluctuations in earnings can cause P/E percentiles to become misleading. For instance, if a company's earnings surge, the P/E ratio may appear low, creating a "value trap" scenario [20][21]. Conclusion - Investments with low percentiles are worth researching, but low percentiles do not guarantee undervaluation. Factors such as short historical data, changes in index rules, different valuation algorithms, and earnings volatility can lead to percentile failures, necessitating a detailed analysis of each situation [25][26].