基础化工行业周报：PTA板块涨幅明显，硫磺、顺酐等价格上涨-2025-03-17

Investment Rating - The industry investment rating is "Overweight" [1] Core Views - The chemical sector's overall performance ranked 19th with a fluctuation of 1.59% during the week of March 8-14, 2025, outperforming the Shanghai Composite Index by 0.19 percentage points and the ChiNext Index by 0.61 percentage points [3][26] - The report highlights a continued trend of divergence in the chemical industry in 2025, recommending attention to sectors such as synthetic biology, pesticides, chromatography media, sweeteners, vitamins, light hydrocarbon chemicals, COC polymers, and MDI [4] Summary by Sections Industry Review - The chemical sector's performance for the week was 1.59%, with the top three performing sub-sectors being nitrogen fertilizers (5.16%), oil and gas refining (4.63%), and synthetic resins (4.55%) [26][27] - The top three individual stocks in the chemical sector were Kexin New Source (26.5%), Aoyang Health (18.1%), and Nuofeng (16.0%) [32] Supply-Side Tracking - A total of 136 companies in the chemical industry had their production capacities affected, with 7 new maintenance cases and 3 restarts reported [15] Key Industry Dynamics - The report notes the imminent implementation of quota policies for third-generation refrigerants, which are expected to enter a high prosperity cycle due to supply constraints and stable demand growth from markets like heat pumps and cold chains [5] - The electronic specialty gases market is highlighted as a critical area for domestic substitution opportunities, driven by rapid upgrades in downstream industries such as integrated circuits and photovoltaics [6][8] - The light hydrocarbon chemical trend is identified as a global movement, with a shift towards lighter raw materials for olefin production, which is expected to enhance the value of leading companies in this sector [8] - The COC polymer industry is experiencing accelerated domestic industrialization, with significant breakthroughs in production capabilities and increasing demand from various applications [9] - The potassium fertilizer market is anticipated to rebound as major suppliers reduce production and inventory pressures ease, with a recommendation to focus on leading companies in this field [10] - The MDI market is characterized by oligopoly, with a favorable supply structure expected to improve as demand recovers, making it a resilient chemical product through economic cycles [13]