Expropriation in investment law is a state taking or destroying the value of an investor’s property. Direct expropriation — formal seizure or transfer of title — is rarely the live issue. What is litigated is indirect or creeping expropriation, where regulation, taxation, licence revocation or a sequence of smaller measures deprives an investment of its value without anyone taking title. The hard question is always where legitimate regulation ends and compensable taking begins, and no authority answers it in the abstract: the test comes from the applicable treaty and from how tribunals have read that treaty’s wording. Newer agreements often address the boundary expressly, providing that non-discriminatory measures designed to protect public welfare objectives do not constitute indirect expropriation except in rare circumstances. Whether that language is present is the first thing to check.
Why this entry carries no source list. This term has no central definition because it is defined treaty by treaty. What it means for a given investment is set by the particular agreement’s own text, and the tribunals interpreting one treaty are not bound by those interpreting another. Citing one instrument would imply a generality that does not exist. Read the treaty that covers your investment, and read how tribunals have construed its wording.