Group 1 - The stock market experienced significant volatility, with a sharp rise followed by a decline, described as a "roller coaster" effect [6] - The People's Bank of China (PBOC) conducted a 240.8 billion yuan reverse repurchase operation, with a net injection of 212.2 billion yuan after 28.6 billion yuan of reverse repos matured [3][5] - The 10-year government bond yield fluctuated, opening at 1.85%, peaking at 1.8605%, and later dropping to a low of 1.838% before closing at 1.843% [5][8] Group 2 - Import and export data for December exceeded expectations, contributing to market movements [5] - Regulatory measures were implemented to increase the margin requirement for new financing contracts, aimed at cooling down the stock market [6] - The bond market showed mixed reactions, with bond yields experiencing fluctuations throughout the day [5][6]