Three Theories of Lex Mercatoria

66 Pages Posted: 5 Apr 2013 Last revised: 14 Jul 2015

See all articles by Gilles Cuniberti

Gilles Cuniberti

University of Luxembourg; Universite du Luxembourg - Faculty of Law, Economics and Finance

Date Written: February 1, 2014


One of the most remarkable developments in international commercial law over the last fifty years has been the gradual acceptance of the existence of a new merchant ‘law’, or lex mercatoria, spontaneously generated by the international community in the shadow of national legal orders. While the notion that there might be law beyond the state aroused the interest of legal scholars and theorists around the world, few wondered whether international commercial actors had a genuine interest in the development of an autonomous transnational law. This Article offers empirical evidence suggesting that commercial parties almost never opt into lex mercatoria pursuant to their freedom to contract, but instead use that freedom to select a particular national law to govern their contracts. This conclusion begs the question of whether anybody else might benefit from lex mercatoria.

In a groundbreaking article published in 2005, Christopher Drahozal argued that the idea had lost practical significance and offered a signaling theory of lex mercatoria: the interest in the idea can be explained by the willingness of would be arbitrators to market themselves. While essentially agreeing with Drahozal, this Article offers two other theories explaining the development of lex mercatoria. First, I argue that deciding disputes on the basis of lex mercatoria can bring important benefits to international arbitrators. If that is the case, though, their interests may conflict with that of the parties who hired them. That raises an agency problem which needs to be both acknowledged and addressed. Secondly, I demonstrate how lex mercatoria can also benefit organizations which are involved in the business of producing model contracts and maintain that the active promotion of the use of non-state law – thereby side-stepping mandatory rules of national law – is intended to reduce the costs of producing international model contracts by such organizations.

Keywords: Transnational law, arbitration, private international law, private ordering, international chamber of commerce, UNIDROIT

Suggested Citation

Cuniberti, Gilles, Three Theories of Lex Mercatoria (February 1, 2014). Columbia Journal of Transnational Law, Vol. 52, No. 1, 2013; University of Luxembourg Law Working Paper No. 2013-1. Available at SSRN:

Gilles Cuniberti (Contact Author)

University of Luxembourg ( email )

Faculté de Droit
4, rue Alphonse Weicker
Luxembourg, 2721

Universite du Luxembourg - Faculty of Law, Economics and Finance ( email )

4 rue Alphonse Weicker
Luxembourg, L-2721

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