Nucor Corporation (NUE) saw its shares plummet 5.09% in after-hours trading on Monday, despite reporting better-than-expected second-quarter earnings. The steel giant's stock decline appears to be driven by the company's disappointing outlook for the third quarter and ongoing concerns about rising raw material costs.

For the second quarter ended July 5, Nucor reported earnings per share (EPS) of $2.60, down from $2.68 a year earlier but surpassing the analyst consensus estimate of $2.55. The company's revenue rose 4.7% to $8.46 billion, slightly below the expected $8.54 billion. Notably, Nucor's adjusted net income for the quarter was $706 million, significantly higher than the $557 million analysts had projected.

However, the positive Q2 results were overshadowed by Nucor's cautious outlook. The company stated it expects third-quarter earnings to be "nominally lower" than the second quarter of 2025, citing decreased earnings in the steel mills segment and similar results in the steel products and raw materials segments. This forecast appears to have spooked investors, leading to the sharp after-hours sell-off. Additionally, rising raw material costs continue to pressure the company's steelmaking segment, potentially impacting future profitability. As the steel industry navigates through these challenges, investors will be closely monitoring Nucor's ability to maintain its performance in the face of increasing input costs and potential market headwinds.