This study tests for changes in U.S.-listed foreign firms’ financial reporting properties and transparency when their home market regulators enter an arrangement that facilitates enforcement cooperation with the Securities and Exchange Commission (SEC). This arrangement—the International Organization of Securities Commissions (IOSCO) Multilateral Memorandum of Understanding Concerning Consultation and Cooperation and the Exchange of Information (MMoU)—has explicit disclosure-related provisions. I show that cooperation is associated with (i) increased cross-border disclosure-related enforcement by the SEC; (ii) improvements across various measures of accounting properties (including earnings management, benchmark beating, and value relevance); and (iii) enhanced firm-level transparency as measured by return synchronicity. Generally, the effects are larger for firms from countries with weaker regulatory quality, which supports enforcement as the mechanism driving the results. This finding helps resolve questions about why the earnings quality of U.S.-listed foreign firms diverged from that of U.S. firms during pre-MMoU periods.