On January 16, the price trend of phthalic anhydride in East China fluctuated and consolidated. The mainstream quotation for phthalic anhydride produced via the ortho-xylene method was 6,100–6,300 yuan/ton, while the market price for phthalic anhydride produced via the naphthalene method ranged from 5,700 to 6,050 yuan/ton. The price of industrial naphthalene fluctuated and stabilized, while the price of ortho-xylene fluctuated and rose, leading to an increase in the cost of phthalic anhydride. The downstream plasticizer market fluctuated and rose, with plasticizer manufacturers maintaining stable equipment operating rates. Downstream demand remained rigid, with procurement of phthalic anhydride primarily based on immediate needs. Demand support for phthalic anhydride persisted, while phthalic anhydride manufacturers maintained stable equipment operating rates, ensuring sufficient supply. Phthalic anhydride inventories remained low. It is expected that the phthalic anhydride market will continue to fluctuate and consolidate in the near future.