On January 14, the phthalic anhydride market in Shandong region showed a strong consolidation trend. The mainstream negotiated prices for o-xylene-based phthalic anhydride were 6,100–6,350 yuan/ton, while those for naphthalene-based phthalic anhydride were 5,700–6,050 yuan/ton. The price of raw material o-xylene fluctuated upward, while industrial naphthalene prices stabilized. The cost of phthalic anhydride increased, and downstream plasticizer markets also exhibited strong consolidation. Phthalic anhydride manufacturers reduced equipment operations, leading to a decline in the operating rate of phthalic anhydride enterprises. The supply in the phthalic anhydride market remained ample, and the operating load of plasticizer enterprises decreased. Despite this, rigid demand for phthalic anhydride persisted, and the market outlook is expected to remain in a strong consolidation phase.