Trinseo shares surge 29.99% after-hours after announcing 35€/ton polystyrene price increases in Europe effective January 1, 2026.

Trinseo (NYSE: TSE) surged 30.0% in after-hours trading following announcements of price increases for its European polystyrene products. The company and its European affiliates announced a 35 Euro per metric ton increase for all polystyrene grades, effective January 1, 2026, aiming to offset rising costs and strengthen margins. This strategic pricing action, coupled with a second report highlighting further planned increases, signaled improved profitability expectations, driving the sharp post-market rally. While a separate report noted ongoing challenges with NYSE listing requirements and financial losses, the immediate price reaction was driven by the positive pricing news, which aligns with the company’s focus on specialty material solutions and operational resilience.