The Stop EU Overreach Act requires the United States Trade Representative to launch a formal investigation into whether four major European Union regulations unfairly burden American companies and restrict U.S. commerce. The targeted regulations cover corporate sustainability reporting, supply chain due diligence, deforestation tracking, and carbon border adjustment mechanisms, which the bill argues impose costly extraterritorial requirements on U.S. firms and their overseas operations even when those operations comply with American law. The USTR must initiate the investigation within 30 days of enactment and complete a determination within 12 months, with the ability to request a single 60-day extension, after which the USTR may recommend trade actions such as tariffs or suspension of trade benefits if the investigation finds the EU practices unreasonable. The legislation also requires the USTR to report to Congress at 90 days and again after making a final determination, detailing preliminary findings and any proposed remedies. The law's requirements end if the EU repeals or amends these measures to eliminate their application to U.S. persons, or enters into a binding agreement exempting American companies from the extraterritorial obligations.