On January 4, the market price of phthalic anhydride in Jiangsu region remained strong and stable. The mainstream negotiation price for ortho-xylene-based products ranged from 5,800 to 6,000 yuan/ton, while the mainstream negotiation price for naphthalene-based products ranged from 5,500 to 5,750 yuan/ton. The operating rate of phthalic anhydride plants increased slightly, leading to a rise in the overall production capacity. The domestic phthalic anhydride market had ample spot supply. The price of raw material ortho-xylene rose sharply, while the price of industrial naphthalene remained stable, resulting in increased cost support for phthalic anhydride. The downstream plasticizer market experienced a strong upward trend, but the operating load of plasticizer enterprises declined, leading to increased demand support for phthalic anhydride. Downstream industries maintained rigid procurement, and the phthalic anhydride market is expected to remain strong and stable in the near future.