Lex mercatoria
A body of rules and customs of international trade, created by business practice, forming a transnational legal order.
Lex mercatoria ('law of merchants') refers to the body of rules, principles and customs of international trade that have developed autonomously from national legal systems, forming a transnational legal order.
Sources of the lex mercatoria include:
- UNIDROIT Principles of International Commercial Contracts (2016 edition)
- Incoterms of the ICC (delivery rules)
- UCP 600 (documentary credits), URC 522 (collections), URDG 758 (guarantees)
- Trade usages recognised in specific sectors (oil, commodities, maritime)
- International arbitral case law
Lex mercatoria is regularly invoked in international arbitration, either as the governing law of the contract (chosen by the parties) or as a supplement to the applicable national law. Some arbitral tribunals apply it when parties have not chosen a governing law.
Its legal nature remains debated: some regard it as a genuine autonomous legal order, others as a mere set of customs lacking independent binding force. In practice, it plays an essential role in the predictability and harmonisation of international commercial transactions.