Core Natural Resources, Inc. (CNR) experienced a significant pre-market plunge, with its stock price falling 5.04% during Thursday's pre-market trading session.

The sharp decline follows the company's release of its fourth-quarter 2025 financial results, which revealed a substantial earnings per share (EPS) miss. Core Natural Resources reported a quarterly loss of $1.54 per share, which fell far short of the analyst consensus estimate for a loss of $0.26 per share. Furthermore, the company's adjusted EBITDA of $103.1 million missed the IBES estimate of $119.2 million. The results were impacted by higher maintenance-related expenses and depressed volumes at certain operations.

Although the company reported quarterly sales of $1.042 billion, beating estimates, the significant losses and missed profitability metrics appear to have driven negative investor sentiment, leading to the pre-market sell-off. The company has resumed longwall mining at key sites and increased its contracted position, but near-term cost pressures weighed on the quarterly performance.