Are Bilateral Investment Treaties (BITs) fit for purpose – to help resolving disputes between investors and states in an efficient, fair and non-politicised manner? One of the bigger cases in the past years – involving the expropriation by the Argentinean government of Repsol’s majority stake in energy firm YPF – has now been settled. And the case offers several lessons for Europe and others that want the system of international investment arbitration to improve. Challenged by groups and parties that want to end or substantially reduce the right for investors to bring cases against states – generally or only in the case of the Transatlantic Trade and Investment Partnership (TTIP) – the EU now reviews its investment protection policy. While reforms are called for, they should improve and not erode the basic principles of BITs.