This analysis focuses on how the European Union (EU) succeeded in bringing the International Accounting Standards (IAS) to being accepted as the international accounting standards. It overcame resistances mainly from the U.S. which considered its accounting stan-dards, US GAAP, to be the superior ones and had been reluctant in supporting EU’s attempt ofthis. Michael L. Katz’s and Carl Shapiro’s model of network externalities is conceptually applied to this case. First, EU regulated all EU listed companies to use IAS from 2005 onwards. Second, it announced that it would apply this regulation to non EU companies from 2007 onwards. Non EU companies were regulated not to have access to EU financial markets for raising capital unless they ...