从事件挖掘绝对收益：指数成分股调整

Group 1: ETF Market Growth - As of April 2025, the total scale of major market index ETFs has increased nearly fourfold compared to the end of 2021[8] - The scale of the CSI 300, CSI 500, and CSI 1000 ETFs reached CNY 10,773 billion, CNY 1,441 billion, and CNY 1,409 billion respectively, with increases of CNY 9,274 billion, CNY 659 billion, and CNY 1,382 billion since the end of 2021[8] - The scale of the SSE 50, STAR 50, and ChiNext Index ETFs reached CNY 1,706 billion, CNY 1,664 billion, and CNY 1,156 billion respectively, with increases of CNY 988 billion, CNY 1,234 billion, and CNY 930 billion since the end of 2021[8] Group 2: Index Component Adjustments - The adjustment of index components occurs biannually in May and November, with implementation dates on the second Friday of the following month[15] - The average prediction accuracy for the CSI 300's adjustments is 87% for additions and 91% for deletions, with recent adjustments showing 93% and 91% accuracy respectively[23] - The average coverage rate for the CSI 300's adjustments is 89% for additions and 93% for deletions[23] Group 3: Investment Opportunities - The study identifies significant Alpha return characteristics in the sample combinations of stocks added and removed during index adjustments[25] - Liquidity shock factors significantly affect the performance of stocks during index adjustments, indicating potential investment opportunities[25]