This paper focuses on the new rules on qualifications of, and ethics applicable to, the members of investment tribunals to be established under the investment chapters of various free trade agreements (FTAs), such as the CETA the TTIP proposal, and EU – Vietnam FTA. This paper first seeks to identify whether the rules live up to their promise of fostering “trust” among stakeholders. To this end, the paper focuses on ‘legitimacy’ as an operative concept. Second, it seeks to understand how the EU seeks to replace the soft law framework currently in place. It will specifically scrutinize the binding nature of the new rules, as well as their compatibility within the context of permanent, appointed judges. It will examine whether they offer clarity in light of appointment and practice of arbitrators. To that end, the research will additionally benefit from previous scholarly and empirical work on actors in international investment law such as legal counsel, arbitrators and expert witnesses.