国泰海通证券研究·2025-05-26 14:53Core Insights - The article predicts the adjustment list for major market index constituents as of June 2025, utilizing refined financial loss identification rules and a review mechanism for securities [1][2] - It highlights significant Alpha return characteristics in the sample combinations of stocks added or removed during index adjustments, particularly through liquidity shock factor grouping [1][2] Market Index ETF Scale - As of April 2025, the scale of various ETFs such as SSE 50, STAR 50, CSI 300, CSI 500, CSI 1000, and ChiNext Index are 170.6 billion, 166.4 billion, 1077.3 billion, 144.1 billion, 140.9 billion, and 115.6 billion respectively [1] - The overall scale of these index ETFs has increased nearly fourfold compared to the end of 2021, indicating a growing trend towards index-based investment [1] Index Adjustment Rules and Historical Testing - The article outlines that the CSI and National Index series are adjusted twice a year, with a high prediction accuracy and coverage rate of around 90% for the CSI 300 index adjustments [2] - It emphasizes the significant Alpha return characteristics observed in the sample combinations during the prediction and announcement periods of index adjustments [2] Arbitrage Strategy Research - Since the second half of 2019, single adjustment absolute returns have been 18.36%, with long-short returns at 23.89% and excess returns at 15.10% [2] - Annual adjustment absolute returns reached 40.09%, with long-short returns at 50.84% and excess returns at 33.47% [2]