Core Viewpoint - Event-driven research is a significant quantitative strategy that focuses on analyzing and utilizing specific events' impacts on asset prices, particularly stock prices, to identify investment opportunities and risks [2][10]. Group 1: Pricing Efficiency in A-Share Market - The A-share market shows high pricing efficiency for events like high growth performance and earnings pre-announcement, with an average excess return of about 1% on the announcement day. However, the continuation of excess returns post-announcement is weak unless earnings exceed market expectations by 20%, leading to an average cumulative excess return of 1.8% over the next 10 trading days for such cases [2][26]. Group 2: Stock Buybacks and Dividends - High dividend announcements lead to significant excess returns, averaging 2.1% over the following 20 days, with a win rate of 58.9%. In contrast, stock buyback events show varied responses based on the purpose of the buyback, with certain types yielding long-term excess returns of up to 6.5% over 60 trading days, especially for stocks with lower research coverage [3][4]. Group 3: Signals from Re-financing - Different forms of re-financing, such as private placements and convertible bonds, generally have a negative impact on stock prices post-announcement. However, private placements that do not include institutional investors can yield some excess returns, albeit with lower win rates [4][6]. Group 4: Impact of Equity Incentives - Announcements of equity incentives and employee stock ownership plans generally have a positive impact on stock prices, with significant excess returns observed over 20 and 60 trading days. The effectiveness of these events is influenced by the scope and intensity of the incentives [4][5]. Group 5: Changes in Sell-Side Views - Significant changes in sell-side views, particularly when accompanied by upward revisions in earnings forecasts and titles indicating "better than expected," are noteworthy. These events yield average cumulative excess returns of 3.8% over 5 days and 6.6% over 60 days [5][6]. Group 6: Institutional Research Behavior - Attention should be given to institutional research events occurring a year after previous coverage, as these often indicate potential undervalued opportunities. The average cumulative excess returns for such events can reach 6.1% over 120 days [6][7]. Group 7: Major Shareholder Actions - Major shareholder buyback announcements are particularly noteworthy when preceding stock performance has been poor. In cases where the prior 20-day excess return is negative, subsequent buyback announcements can lead to average excess returns of 6.5% over 120 days [6][7]. Group 8: Index Adjustments and Passive Fund Flows - Stocks included in indices experience significant positive impacts from passive fund flows, with average cumulative excess returns of 5-6% around the announcement date. Predicting index adjustments can help investors capture these excess returns [6][8]. Group 9: Opportunities in Large-Cap Stocks - For large-cap stocks (over 50 billion), key events to monitor include earnings announcements exceeding consensus expectations by 20%, which can yield average excess returns of 3.9% over 60 days [7][8]. Group 10: Negative Signals to Watch - Certain events, such as large-scale financing, lock-up expirations, and significant shareholder sell-offs, indicate heightened downside risks. These events often lead to negative excess returns over extended periods [8][9].