This paper delves into the relationship between trade and competition, which has long been a subject largely untouched since the issue had been dropped from the multilateral trade agenda in 2003. The need to incorporate elements of competition policy into international trade rules has long been discussed in the context of making the international trade regime more effective. The issue has gained more attention as state-owned enterprises (SOEs) began to emerge as new influential players in the international market, competing with private enterprises on an unequal footing. A growing number of bilateral trade agreements have included chapters on competition policy, albeit with rules that do not have sufficient binding force for disciplining the business practices of state-owned enterprises. The recently concluded Trans-Pacific Partnership (TPP), however, has introduced innovative rules for disciplining the competitive practices of SOEs by integrating the existing WTO disciplines on subsidies with competition rules. In this article, “competitive neutrality”, the fundamental principle underlying the SOE disciplines, is used as a framework of analysis for understanding the new disciplines and obligations in the SOE rules. Several legal issues and challenges are identified that are relevant for applying the new rules in the real world, and implications are derived for future rule-making involving other new trade issues.