Trinseo PLC Securities Lawsuit Investigation

Shamis & Gentile P.A., a law firm that advocates for investors who are victims of securities fraud, is investigating potential claims against Trinseo PLC (TSE)

If you purchased or otherwise acquired Trinseo PLC securities between July 2024 and early-October 2025, and suffered losses, you may be eligible to join this securities investigation and seek compensation.

About Trinseo PLC

Trinseo PLC is a specialty materials company focused on the production of plastics, latex binders, and synthetic rubber.

The company operates globally, with a particular emphasis on developing innovative solutions for the automotive, consumer goods, and industrial markets.

Potential Concerns Under Investigation

Attorneys are reviewing whether Trinseo PLC and its executives made false or misleading statements, or failed to disclose material information, between July 2024 and early-October 2025.

During this time, Trinseo promoted its sustainability and circular-economy initiatives, particularly its Rho, Italy depolymerization plant. The company described the facility as a “significant step forward in the company's commitment to sustainability,” allegedly claiming it would produce recycled MMA monomer with purity levels comparable to virgin methyl methacrylate (MMA) for high-end applications.

Throughout late 2024 and early 2025, executives allegedly emphasized strong financial and operational momentum, citing a “seventh consecutive quarter of year-over-year Adjusted EBITDA improvement” and “ample runway to continue pursuing our strategy.”

However, by mid-2025, the company faced weak demand, high energy prices, and increased competition from imports, particularly in Europe, raising questions about whether these risk factors were properly disclosed to investors.

On August 6, 2025, Trinseo reported second-quarter results that missed expectations (EPS of ~$2.12 versus an estimated ~$1.50). Following this announcement, the stock price fell almost 20%, closing near $2.06 per share.

Two months later, on October 6, 2025, Trinseo announced the permanent closure of its Italy MMA and ACH plants, including the Rho facility, along with the indefinite suspension of its quarterly dividend.

The company continued paying quarterly dividends through 2024 and 2025, allegedly giving no prior indication of a possible suspension. The announcement caused the stock to fall an additional 10.9%, from opening at $2.30 on October 6 to closing at $2.05 on October 7, 2025, erasing millions of dollars in market value.

These developments have prompted questions about whether Trinseo accurately represented its financial health and the operational status of its key facilities. Attorneys may also examine whether the company's executives exercised appropriate oversight and disclosure regarding the company’s strategic and financial communications.

Your Rights and Next Steps

This is an ongoing investigation and not a filed lawsuit. Investors who purchased or held Trinseo PLC securities between July 2024 and early-October 2025, and suffered losses may have legal rights. If the investigation uncovers evidence of securities law violations, it could lead to a class action lawsuit seeking to recover losses for affected shareholders.

Lawyers are ready to help investors understand their options and protect their interests. Participating in the investigation does not require any upfront cost, and investors may be able to join a potential class action if one is filed in the future. It is important for investors to act promptly, as securities investigations are time-sensitive and deadlines can affect eligibility.

You May Be Entitled to Compensation

If you purchased or acquired Trinseo PLC securities between July 2024 and early-October 2025, and experienced financial losses, you may be eligible to participate in this investigation and seek compensation. Securities investigations move quickly, and acting now can help preserve your rights.

To join the investigation, complete the form below.