据了解，上证龙头企业指数选取沪市各二级行业中规模大、市场占有率高的龙头公司证券作为指数样 本，以反映沪市各行业龙头上市公司证券的整体表现。该指数以2003年12月31日为基日，以1000.0点为 基点。 资料显示，指数样本每半年调整一次，样本调整实施时间分别是每年6月和12月的第二个星期五的下一 交易日。权重因子随样本定期调整而调整，调整时间与指数样本定期调整实施时间相同。在下一个定期 调整日前，权重因子一般固定不变。特殊情况下将对指数进行临时调整。当样本退市时，将其从指数样 本中剔除。样本公司发生收购、合并、分拆等情形的处理，参照计算与维护细则处理。 从指数持仓来看，上证龙头企业指数十大权重分别为：衢州发展（1.44%）、工业富联（1.35%）、药 明康德（1.3%）、恒生电子（1.26%）、华勤技术（1.23%）、中航沈飞（1.22%）、包钢股份 （1.21%）、小商品城（1.19%）、五矿资本（1.19%）、上汽集团（1.16%）。 数据统计显示，上证龙头企业指数近一个月上涨4.37%，近三个月上涨4.10%，年至今下跌0.04%。 从上证龙头企业指数持仓样本的行业来看，工业占比19.92%、可选消费占 ...

Group 1 - The A-share market's three major indices closed mixed, with the Shanghai Leading Enterprises Index down 0.01% at 3180.99 points and a trading volume of 79.626 billion yuan [1] - The Shanghai Leading Enterprises Index has increased by 0.25% over the past month, decreased by 1.96% over the past three months, and has fallen by 3.37% year-to-date [1] - The index selects leading companies from various secondary industries in the Shanghai market based on their size and market share, reflecting the overall performance of leading listed companies [1] Group 2 - The top ten weights in the Shanghai Leading Enterprises Index are: Guotai Junan (2.49%), Xiaoshangpin City (1.42%), Hailan Home (1.3%), China Merchants Bank (1.27%), Zijin Mining (1.24%), China Telecom (1.22%), Morning Light Co. (1.2%), COSCO Shipping (1.2%), Industrial and Commercial Bank of China (1.19%), and Agricultural Bank of China (1.19%) [1] - The index's holdings are entirely composed of companies listed on the Shanghai Stock Exchange, with a 100% representation [1] Group 3 - The industry composition of the index includes: Industrial (19.28%), Consumer Discretionary (14.74%), Materials (12.28%), Financials (12.05%), Communication Services (9.36%), Information Technology (8.76%), Consumer Staples (8.27%), Healthcare (6.39%), Energy (3.06%), Utilities (3.03%), and Real Estate (2.78%) [2] - The index samples are adjusted biannually, with adjustments implemented on the next trading day following the second Friday of June and December each year [2] - Weight factors are generally fixed until the next scheduled adjustment, with special circumstances allowing for temporary adjustments [2]