Group 1 - The Shanghai Composite Index opened lower and the CSI 300 Food Index reported 7270.47 points, indicating a recent decline in the food sector [1] - The CSI 300 Food Index has decreased by 2.82% over the past month, 7.95% over the past three months, and 10.52% year-to-date [1] - The CSI 300 Index categorizes its 300 sample stocks into 11 primary industries, 35 secondary industries, over 90 tertiary industries, and more than 200 quaternary industries, providing a comprehensive analysis tool for investors [1] Group 2 - The CSI 300 Food Index is primarily composed of stocks from the Shanghai Stock Exchange, which accounts for 84.47%, while the Shenzhen Stock Exchange accounts for 15.53% [1] - Within the holdings of the CSI 300 Food Index, dairy products represent 61.67%, condiments and cooking oils account for 29.13%, and meat products make up 9.20% [1] Group 3 - The index samples are adjusted biannually, with adjustments occurring on the next trading day after the second Friday of June and December [2] - Weight factors are generally fixed until the next scheduled adjustment, but can change with temporary adjustments due to special events affecting sample companies [2] - Companies that are delisted or undergo mergers, acquisitions, or splits will be handled according to specific calculation and maintenance guidelines [2]

Group 1 - The core viewpoint of the articles highlights the performance of the CSI 300 Food Index, which closed at 7859.35 points, showing a decline of 0.33% over the past month, an increase of 2.02% over the past three months, and a year-to-date decline of 3.28% [1] - The CSI 300 Food Index is categorized into various industry sectors, including 11 primary industries, 35 secondary industries, over 90 tertiary industries, and more than 200 quaternary industries, providing a comprehensive analysis tool for investors [1] - The index is based on the performance of 300 sample securities from the CSI 300 Index, with a base date of December 31, 2004, and a base point of 1000.0 [1] Group 2 - The market share of the CSI 300 Food Index is predominantly from the Shanghai Stock Exchange at 84.29%, while the Shenzhen Stock Exchange accounts for 15.71% [2] - Within the holdings of the CSI 300 Food Index, the dairy sector represents 61.22%, followed by condiments and edible oils at 29.41%, and meat products at 9.37% [2] - The index samples are adjusted biannually, with adjustments occurring on the next trading day after the second Friday of June and December each year, ensuring that the weight factors are updated accordingly [2]