On January 13, the phthalic anhydride market in Shandong region showed a strong consolidation trend. The mainstream negotiation price for ortho-xylene-based phthalic anhydride was 6,100–6,350 yuan/ton, while that for naphthalene-based phthalic anhydride was 5,700–6,050 yuan/ton. The price of raw material ortho-xylene fluctuated upward, while the price of industrial naphthalene stabilized. The cost of phthalic anhydride increased, and the downstream plasticizer market remained strong with consolidation. Phthalic anhydride manufacturers reduced equipment operation, leading to a decline in the operating rate of phthalic anhydride enterprises. The supply of phthalic anhydride in the market remained sufficient, while the operating load of plasticizer enterprises decreased. However, rigid demand for phthalic anhydride persisted, and the market outlook is expected to remain strong with consolidation.