AEM Holdings Ltd (AWX.SI) saw its stock plummet 3.43% in pre-market trading on Monday following news of a fresh patent infringement lawsuit filed against the company. Advantest Test Solutions, Inc. has lodged a complaint in the U.S. District Court for the Southern District of California, alleging that AEM and its subsidiaries violated two U.S. patents related to a wafer-level test system.

In response to the lawsuit, AEM Holdings strongly denied the allegations, stating that the referenced system is not used in its operations. The company has engaged U.S. legal counsel to contest the suit and emphasized that this new filing does not affect its business operations, products, or ability to serve customers. Despite the legal challenge, AEM reiterated its revenue guidance for the second half of 2025, which was previously issued on August 13, 2025.

This latest legal action comes after both parties settled an earlier arbitration on July 28, 2023. AEM Holdings has advised investors to exercise caution when trading its shares and promised to update shareholders on any material developments regarding the case. The market's negative reaction reflects concerns over potential legal risks and uncertainties surrounding the company's intellectual property position in the semiconductor testing industry.