The global investment regime is governed through a fragmented network of intergovernmental treaties known as international investment agreements (IIAs). At the core of this regime are around 3,200 bilateral investment treaties (BITs). The first generation of these agreements were negotiated at the end of the 1950s and were mostly concluded between a developed and a developing country. This pattern changed during the 1990s when the number of BITs grew exponentially, and developing countries and economies in transition signed BITs among themselves. In addition, investment chapters started to be included in certain preferential trade agreements (PTAs) following the example of NAFTA embedding investment protection in Global Value Chains (GVCs). It is notable that most IIAs allow foreign investors to challenge governmental actions outside local courts, using investor-state dispute settlement (ISDS) provisions to trigger binding investor-State arbitrations. ISDS cases have proliferated in the past 15 years, with the overall number of known treaty-based arbitrations reaching 767 by June 2017. Today, IIAs impact on several other disciplines of international law, including sustainable development, climate change, human rights and international taxation.