ABSTRACT
Typical substantive sustainable development provisions of international investment agreements (IIAs) include expropriation and FET clauses. Expropriation has been a major public international law issue throughout the twentieth century. The rules of international law governing the expropriation of alien property have long been of central concern to foreign investors. A definition of expropriation can be found in customary international law, with "taking of property" as the core meaning. The annex in the 2012 US Model BIT is a typical and popular model in IIA-making. Despite the lack of a uniform definition of state police powers, such powers are generally accepted as a matter of customary international law. A key requirement to justify a non-compensable indirect expropriation under many IIAs is that the state regulatory measure should be taken for public purposes. Serious concerns have also been voiced that the restraining effect of investment protection regimes on host states threatens the ability of these states to pursue sustainable development policies.
