After Brexit, legislators, practitioners, and legal scholars in the EU have to reconsider what may be legally needed to support business increasingly conducted in or from the EU rather than from London. Practically, practitioners and legal scholars will have to ask whether and to what extent a contractual choice of English or alternatively New York law is or remains sufficiently effective and enforceable especially in proprietary and regulatory matters to overcome the basic conflicts of law approach still cutting up transactions in the international business flows into local parts depending on closest connections in the hope that these legal pieces together still present an adequate legal framework for the business as a whole. The true question is then to what extent common law can remain dominant through a party choice of law. More fundamentally, in all international commerce and finance, therefore in international professional dealings, not only this approach but substantive key building blocks of private law may need reconsideration, especially new financial structures and funding mechanisms, to operate and find more universal legal support. This goes well beyond the EU or a party choice of law and affects all national legal systems connected with the international market place and its operation, therefore also the U.S, South America, Japan, China, South Korea, Singapore, India, Indonesia, and many others. The question then is what the alternatives are.It is submitted that transnationalisation of private law is here the more ready and efficient tool and way forward especially in trans-border manufacturing, supply, and distribution chains by accepting, on the one hand, the legal unity of international business transactions and, on the other, the direct application of international fundamental and general principle, custom and market practices, and a strong form of party autonomy subject to transnational minimum standards of behaviour in the international market place. Although the common law is closer, which derives in contract and moveable property law from its origin in commerce, it needs to respect the rules of the international markets and its legal structures just as much to remain truly relevant and move forward. It means that these are issues no less relevant to international business when connected with or operating from the US, the UK, Canada, or Australia or made subject to a contractual choice of their laws. This article attempts to meet this challenge for international assignments of portfolios of monetary claims with assignees in other countries and debtors in many. It is a vital part of the international financial infrastructure. The solution is found in the approximation of monetary claims to, and treatment like, promissory notes, which developed similarly as negotiable instruments under the older law merchant, the applicable law and relevant sources to be found in the manner of public international law pursuant to Art. 38(1) of the Statute of the ICJ, as it was for all law before the 19th Century when nationalisation set in. Assuming globalisation holds, it is submitted that in international commercial and financial dealings we are returning to this earlier model which, in the Grotian manner, in terms of methodology reunites all law formation and application at the international level at least for professional participants
