在成本上行与预售支撑下，本周有机硅价格小幅上行

Investment Rating - The report maintains an "Overweight" rating for the basic chemical industry [5] Core Insights - The basic chemical industry experienced a weekly decline of 1.33% from September 15 to September 19, 2025, ranking 20th among all Shenwan first-level industries [5][11] - The organic silicon price saw a slight increase, with the DMC intermediate price reaching 11,000 CNY/ton, up 1.9% from the previous week, supported by strong pre-sale orders and rising raw material costs [6][12] - The report suggests focusing on specific sectors within the basic chemical industry, including refrigerants constrained by quotas, industries benefiting from "anti-involution" trends like titanium dioxide, and sectors driven by domestic demand such as phosphate fertilizers and civil explosives [8][27] Summary by Sections Industry Overview - The basic chemical industry had a weekly decline of 1.33% from September 15 to September 19, 2025, with the top five gaining stocks being Kaimeite Gases, Guangdong Hongda, Jinghua New Materials, *ST Yatai, and Xinghua New Materials, while the top five losing stocks included Jianbang Co., Runyang Technology, Wankai New Materials, Jiaao Environmental Protection, and Changhua Chemical [5][11] Subsector - Organic Silicon - The organic silicon price increased slightly, with the DMC intermediate price at 11,000 CNY/ton as of September 19, 2025, reflecting a 1.9% rise from the previous week. This increase is attributed to strong pre-sale orders and rising costs of raw materials, particularly metallic silicon [6][12] - The operating rate and production of organic silicon intermediates showed significant month-on-month increases in August [12] Investment Recommendations - The report recommends attention to the following sectors in the basic chemical industry: 1) refrigerants affected by quota constraints (e.g., Juhua Co., Sanmei Co., Yonghe Co., Dongyue Group); 2) industries benefiting from "anti-involution," such as titanium dioxide (e.g., Longbai Group); 3) domestic demand-driven sectors that can mitigate tariff impacts, such as phosphate fertilizers (e.g., Yuntianhua) and civil explosives (e.g., Guangdong Hongda) [8][27]