Eos Energy Enterprises climbed 29.63% to $5.95 on Thursday after announcing first-quarter 2026 revenues of $56 million to $57 million, representing a 433% to 443% increase from $10.5 million in the same period last year. The battery energy storage company attributed the growth to record shipments and strong manufacturing performance. The company cited operational improvements in supplier quality control, lean processes and equipment optimisation as drivers of increased throughput and execution. Shipments remained aligned with customer contractual commitments. Eos Energy also completed factory acceptance testing for its second production line during the quarter, with initial production targeted for late second quarter. The new line incorporates efficiency enhancements including single-piece flow configuration and advanced gantry systems. Official results are due next month.

Driehaus Capital Management purchased 7.70 million shares of Eos Energy Enterprises in the fourth quarter, worth an estimated $110.72 million based on quarterly average pricing, according to a February 17, 2026 SEC filing. The investment increased Driehaus' total stake to 14.27 million shares. Eos Energy, which manufactures grid-scale battery storage systems, has seen shares rise nearly 50% over the past year to $6.12, outperforming the S&P 500's 19% gain. Revenue reached $114.2 million in 2025, more than seven times the prior year, driven by increased deliveries and manufacturing improvements. The company reported a $701.5 million backlog and $23.6 billion commercial pipeline. However, shares have tumbled 47% since last quarter following softer-than-expected revenue guidance, partially reversing recent gains.

Eos Energy Enterprises faces a securities fraud class action lawsuit after its stock fell 39% on 26 February 2026. The lawsuit, filed in the US District Court for the District of New Jersey, alleges the company misrepresented near-term revenue growth and manufacturing capabilities. Eos Energy, which manufactures zinc-based battery energy storage systems, had guided fiscal year 2025 revenue of $150 million to $160 million whilst touting manufacturing progress. However, the company reported a $970 million net loss and missed guidance due to production inefficiencies, battery line downtime and quality delays. The complaint alleges violations of the Securities Exchange Act. Investors have until 5 May 2026 to apply to lead the case. Law firm Bleichmar Fonti & Auld is representing plaintiffs on a contingency basis.