- Index enhancement funds combine passive tracking with active or quantitative strategies to achieve excess returns while maintaining a close tracking of specific market indices (e.g., CSI 300, CSI 500) [11] - The construction of index enhancement funds involves allocating most of the portfolio to index constituent stocks to ensure market-synchronized returns, while the remaining portion is optimized through fundamental stock selection, quantitative models (e.g., multi-factor strategies), IPO participation, or derivatives (e.g., stock index futures) [11] - Broad-based index enhancement funds dominate the market, accounting for approximately 91% of the total index enhancement fund scale as of June 30, 2025, with a scale of 1880.6 billion yuan [2][12] - SmartBeta index enhancement funds, which use factor strategies (e.g., dividends, low volatility) to optimize constituent stock weights, reached a scale of 69.4 billion yuan as of June 30, 2025, after peaking at 102.7 billion yuan in 2023 [12][18] - Industry-based index enhancement funds, composed of stocks from a single industry, reached a scale of 93.1 billion yuan as of June 30, 2025, showing rapid growth since 2021 [12][18] - Thematic index enhancement funds, focusing on cross-industry themes, have maintained a scale below 25 billion yuan with relatively flat growth [12][18] - As of August 1, 2025, the CSI 2000-related index enhancement funds demonstrated the highest median excess return of 11.94% year-to-date, with relatively moderate annualized tracking errors [6][28][31] - Year-to-date, the top-performing indices in terms of excess returns include CSI 2000, CNI 2000, and CSI 1000, all exceeding 4% in excess returns, with moderate tracking errors [2][28][31]