Money laundering has become a phenomenon of financial market regulation. The obligation to identify the ultimate beneficiary, or the beneficiary owner, which need not be entirely synonymous terms, has been the focus of both national authorities and international organizations. However, such identification also has a purely legal dimension. In many countries of the world, identification is a prerequisite for the successful enforcement of rights. Sometimes it also constitutes a requirement necessary for establishing the jurisdiction of courts or other authorities. The set of rules that are thereby created is sometimes referred to as the formation of the modern lex mercatoria. The FATF organization established by the G7 is probably the most important institution that effectively combats money laundering, but there are also other international organizations that draft or participate in the drafting of international treaties, and thereby help create the required legal framework. The European Union has an autonomous position in this area. The identification obligation concerns the main participants on the financial markets and independent professionals. The growing tendencies in this regard will certainly influence the national and international markets in the future.