The U.S. polystyrene market began September 2025 steady but soon turned downward, with prices dropping due to plentiful supply and cautious buying. ChemAnalyst expects price declines in Q4 2025, driven by seasonal slowdowns and excess inventory.
The U.S. polystyrene market started September 2025 on stable ground, carrying over the calm from late August. Buyers stayed careful, keeping an eye on steady styrene feedstock costs and even supply-demand conditions. This followed a 3% price drop in August from July, which settled into four weeks of stable prices. Food packaging and construction insulation held up demand, but weaker orders from other industries kept the market wary.
By mid-September, the polystyrene market took a bearish turn. In the second week, prices dropped 1%, continuing a 12-week slide driven by abundant feedstock, high stockpiles, and steady energy costs that gave no lift to prices. Still, consistent demand for packaged foods, new housing projects needing insulation, and exports helped ease the fall.
The decline deepened by the third week, with polystyrene prices falling 3% due to plentiful benzene and lower contract prices. Some buyers switched to alternatives like polypropylene or polyethylene terephthalate for packaging. Yet, steady demand from packaging, construction, and electronics sectors kept the drop in check. By the last week, polystyrene prices slipped by less than 1%, settling into a weak but steady market with regular buying and production.
Polystyrene production in early September stayed smooth, backed by reliable styrene supply and consistent demand from packaging, electronics, and construction. Major producers kept output steady, with supply chains running well thanks to ample U.S. stockpiles and some imports. Recycled polystyrene, both mechanically and chemically processed, guided production plans. No big disruptions hit, and producers tweaked processes to hold onto profits. In August, some cut back output due to softer demand, but packaging and insulation sectors kept things steady.
Demand for polystyrene stayed solid in key areas. In August, packaging saw steady demand from food and beverage improvements and growing U.S. pharmaceutical production. Flexible plastics held their ground, and PFAS-free, recyclable polystyrene options shaped buying choices. Cautious ordering tied to economic uncertainty matched the August price drop. In electronics, August hit a two-year high in demand, with strong orders, shipments, and production despite rising material and labour costs, boosting polystyrene use in components and casings to help steady the market.
ChemAnalyst predicts price declines for polystyrene in Q4 2025. October may see slower buying, with imports and high stockpiles limiting price rises. Reduced construction could cut demand for insulation-grade polystyrene. November may face pre-holiday slowdowns, softer styrene prices from lower oil costs, and limited exports due to Asian competition. In December, clearing out inventories, holiday factory shutdowns, and weaker demand in construction and packaging will likely weigh on polystyrene market sentiment.
