Olin Corporation (OLN) shares plunged 6.6% in after-hours trading on Thursday, following the company's guidance for weaker first-quarter earnings. The after-hours sell-off came after the closing bell, where shares had finished the regular trading session relatively flat.

The plunge was likely driven by Olin's forecast that its adjusted EBITDA for the first quarter of 2025 will be in the range of $150 million to $170 million. EBITDA, or earnings before interest, taxes, depreciation, and amortization, is a key profitability metric used by investors to gauge a company's operational performance. Lower EBITDA guidance suggests that Olin may report weaker earnings and profits for the upcoming quarter, potentially due to factors like weaker demand, higher costs, or industry challenges.

The market's negative reaction to Olin's Q1 EBITDA forecast highlights investors' concerns about the company's short-term outlook and reflects the importance of meeting or exceeding profitability expectations, especially in the current economic environment.