Substantive law

Rules and principles of law applicable or applied to the resolution of a dispute on its merits. Their origin may be State law (national law), public international law or privately determined law (such as via a contractual agreement to apply lex mercatoria). When the substantive applicable law has not been chosen by the parties, the arbitrators apply the substantive law they deem appropriate taking into account the reasonable expectations of the parties. A distinction has to be made between the substantive law and the procedural law.