On January 8, the market price of phthalic anhydride in Jiangsu region remained firm and stable. The mainstream negotiation price for ortho-xylene-based products ranged from 5,900 to 6,150 yuan/ton, while the mainstream negotiation price for naphthalene-based products ranged from 5,600 to 5,850 yuan/ton. Phthalic anhydride manufacturers reduced equipment operations, leading to a decline in the operating rate of phthalic anhydride production. The domestic phthalic anhydride market had ample spot supply. The price of raw material ortho-xylene fluctuated and rose, while the price of industrial naphthalene remained firm and stable. The cost support for phthalic anhydride increased significantly. The downstream plasticizer market experienced a strong upward trend, with plasticizer enterprises reducing their operating loads. However, demand support for phthalic anhydride remained, driven by rigid downstream procurement. In the later period, the phthalic anhydride market is expected to experience fluctuating growth.