Olin Corporation's stock experienced a significant post-market plunge of 7.25% on Thursday following the release of its fourth-quarter 2025 financial results. The after-hours sell-off came as investors reacted to the company's latest earnings report and disappointing forward guidance.

The chemical and ammunition maker reported quarterly results that missed analyst expectations on several key profitability metrics. Olin's Q4 adjusted EBITDA of $67.7 million fell short of the $74.3 million consensus estimate, while the company posted a loss of $0.75 per share compared to analyst expectations ranging from a loss of $0.53 to $0.72 per share.

Adding to investor concerns, the company provided guidance indicating it expects Q1 2026 adjusted EBITDA to be lower than Q4 2025 levels. Olin cited continued market headwinds, including customer destocking and operational challenges, particularly impacting its Chlor Alkali Products and Vinyls segment, though management noted that its Winchester ammunition business is expected to show modest improvement.