Group 1 - The core index of the A-share market showed mixed performance, with the China Securities Energy Index rising by 0.89% to 2609.76 points, with a trading volume of 9.268 billion yuan [1] - Over the past month, the China Securities Energy Index has decreased by 2.70%, down 8.34% over the last three months, and down 13.01% year-to-date [1] - The top ten weighted stocks in the China Securities Energy Index include China Shenhua (15.98%), China Petroleum (13.33%), and China Petrochemical (12.31%) [1] Group 2 - The China Securities Energy Index is composed entirely of energy sector stocks, with a 100% industry representation [2] - The index samples are adjusted biannually, with adjustments occurring on the next trading day after the second Friday of June and December [2] - Temporary adjustments to the index samples occur when the China Securities 800 Index undergoes changes, and companies that experience special events affecting their industry classification will also lead to adjustments in the index [2]