Shares of Insteel Industries (NYSE: IIIN) surged 10.59% in pre-market trading on Thursday following the release of its impressive second-quarter 2025 financial results. The largest manufacturer of steel wire reinforcing products for concrete construction applications in the United States reported earnings that significantly exceeded analyst expectations, driving investor enthusiasm.

For the quarter ended March 29, 2025, Insteel reported earnings per share (EPS) of $0.52, handily beating the analyst consensus estimate of $0.27 by 92.6%. This represents a substantial increase from $0.35 per share in the same period last year. The company's quarterly sales reached $160.7 million, marking a 26.1% increase from $127.4 million in the prior-year quarter. This top-line figure also surpassed analyst estimates of $149.85 million by 7.21%.

Insteel's strong performance was underpinned by several positive factors. The company saw a significant expansion in its gross margin, which rose to 15.3% from 12.3% in the prior-year quarter. This improvement was attributed to higher shipment volumes, lower unit manufacturing costs, and contributions from recent acquisitions. Net earnings for the quarter stood at $10.2 million, reflecting the company's robust operational execution. Moreover, Insteel's President and CEO, H.O. Woltz III, expressed optimism about the market outlook, citing improving customer demand and rising confidence in the construction industry. This positive sentiment, combined with the better-than-expected financial results, likely fueled investor enthusiasm and contributed to the stock's pre-market rally.