Core Viewpoint - The article discusses the construction and performance of a "limited attention" factor in stock selection, highlighting how investor attention is a scarce resource that influences market behavior and stock performance [1][2]. Limited Attention Factor Construction - The traditional efficient market hypothesis assumes that investors can instantaneously process all new information, but in reality, investors have limited attention, leading to non-rational decision-making [2]. - The "limited attention" factor is constructed using four indicators: abnormal turnover rate, abnormal trading volume, extreme returns, and whether a stock appears on the "Dragon and Tiger List" [3][4]. - The construction methods include linear combination and random forest, with the latter showing better predictive power for returns [4][5]. Factor Performance - The performance of the limited attention factor indicates that stocks with higher attention levels attract more retail investor interest, leading to short-term price increases but often resulting in poor long-term performance [7][8]. - The factor's effectiveness is more pronounced in smaller stock pools, where retail investors' behavior can significantly impact stock prices [13][12]. Implications of Limited Attention Factor - The limited attention factor can signal "money-making effects" in the market, particularly during certain periods when retail investors chase high-attention stocks [14][17]. - The factor's IC (Information Coefficient) shows a correlation with market conditions, suggesting that it can be used for market timing and sector rotation strategies [19][22]. Application of Limited Attention Factor - The factor can be directly used in index enhancement strategies by either adding it to existing predictive models or excluding high-limited attention stocks from selection [25][30]. - Different methods of applying the factor yield varying results, with the addition of the factor generally enhancing performance in larger stock pools [30][41]. - The analysis of other factors within the limited attention domain reveals that growth and low volatility factors perform better, while profitability and value factors show decreased effectiveness [32][41].

Core Viewpoint - The article discusses the construction and performance of a "limited attention" factor in stock selection, highlighting how investor attention is a scarce resource that influences market behavior and stock performance [1][2]. Limited Attention Factor Construction - The traditional efficient market hypothesis assumes that investors can instantaneously process all new information, but in reality, investors have limited attention, leading them to focus on high-attention stocks [1]. - The article constructs the limited attention factor using four indicators: abnormal turnover rate, abnormal trading volume, extreme returns, and whether a stock has appeared on the "Dragon and Tiger List" [2][3]. - The abnormal turnover rate is calculated by comparing a stock's daily turnover to its average turnover over the past 252 trading days [2]. - The abnormal trading volume is similarly calculated by comparing a stock's daily volume to its average volume over the past 252 trading days [2]. - Extreme returns are determined by measuring the deviation of a stock's daily return from the average return of all stocks on that day [2]. - The final limited attention factor is constructed using both linear combination and random forest methods, with the latter providing better predictive power for returns [3][4]. Factor Performance - The performance of the limited attention factor is evaluated based on its ability to capture retail investor interest, with higher attention stocks showing a significant increase in shareholder accounts [5][7]. - The random forest method shows higher information coefficient (IC) and win rate compared to the linear combination method, indicating better performance in distinguishing between high and low attention stocks [8][12]. - The factor performs best in smaller stock pools, where retail investors' trading behavior can significantly impact stock prices [13]. Implications of Limited Attention Factor - The limited attention factor can indicate "money-making effects" in the market, with its performance varying across different market conditions [14][17]. - The factor's IC showed a notable decline from 2019 to mid-2021, suggesting that high attention stocks were profitable during that period, while subsequent periods indicated poor performance for these stocks [17][19]. - The article explores the use of the limited attention factor for market timing and size rotation strategies, achieving a monthly win rate exceeding 70% [19][22]. Application of Limited Attention Factor - The limited attention factor can be directly used in index enhancement strategies, either by adding it to existing predictive factors or by excluding high attention stocks from the selection process [25][29]. - The results indicate that directly adding the limited attention factor improves performance in the CSI 300 and CSI 500 indices, while excluding high attention stocks does not yield better results [30][31]. - The article also examines the performance of other factors within different limited attention domains, finding that growth and low volatility factors perform better in high attention stocks, while profitability and value factors show decreased effectiveness [32][33]. Conclusion - The limited attention factor effectively represents the degree of retail investor interest in stocks, with its average IC being negative, indicating that high attention stocks may face greater pullbacks due to lack of long-term support [41][42]. - The factor's performance can reflect market "money-making effects," and its application in stock selection can enhance portfolio performance, particularly in simpler selection methods [41][42].

Core Insights - The report constructs a "limited attention" factor that represents the degree of retail investor attention on individual stocks, using indicators such as abnormal turnover, abnormal trading volume, extreme returns, and whether the stock has appeared on the "Dragon and Tiger List" [3][6][56] - The limited attention factor can indicate a "money-making effect," showing a high success rate for timing signals, with an overall monthly success rate exceeding 70% when applied to the CSI 300 index [3][25][56] - The factor performs better in smaller stock pools, indicating that retail investors' "herding behavior" can lead to significant price fluctuations in these stocks [3][56] Limited Attention Factor Construction - The construction of the limited attention factor is based on the premise that retail investors prioritize stocks that attract their attention, leading to a focus on high turnover, high trading volume, and extreme returns [6][8] - The factor is constructed using both linear combination and random forest methods, with the latter showing better predictive power for returns [13][14][19] Performance of the Limited Attention Factor - The performance of the limited attention factor is evaluated through its information coefficient (IC) and the average change in shareholder accounts, indicating a clear relationship between higher attention levels and increased retail investor interest [18][19] - The factor's IC and monthly long-short returns are notably higher in the CSI 1000 index, aligning with the logic that smaller stocks are more susceptible to retail investor behavior [22][24] Money-Making Effect Indication - The report highlights that the limited attention factor's IC can reflect the strength of the market's "money-making effect," particularly during the period from 2019 to mid-2021 when retail investors showed strong interest in high attention stocks [25][27][32] - The correlation between the limited attention factor's IC and industry trend consistency indicates that higher IC values suggest better market performance [29][30] Application of the Limited Attention Factor - The factor can be directly used in index enhancement strategies, either by adding it to existing models or by excluding stocks with high limited attention [35][37] - The report finds that directly adding the limited attention factor improves performance in the CSI 300 and CSI 500 indices, while both methods fail to enhance returns in the CSI 1000 index [40][57] Performance of Other Factors in Limited Attention Domains - The report identifies that price-volume factors, particularly low volatility, low liquidity, and long-term momentum, perform significantly better in the limited attention domain, while profitability, valuation, and dividend factors show decreased effectiveness [41][42][43] - The analysis of different stock pools reveals that the performance of factors varies significantly between limited attention and non-limited attention stocks, with growth and price-volume factors being more effective in the former [41][44]