British think tank New Financial bases its Global Financial Centers Index on 73 indicators, mainly those measuring the size and volume of financial activities.
In a complementary study, New Financial analyses the level of internationalization of the different financial centers. It ranks Luxembourg as the most international financial center in the world, with international activity representing 60% of its total activity. The country is followed by Singapore, Hong Kong, the UK and Ireland.
https://www.tradeandinvest.lu/news/luxembourg-among-the-top-10-financial-centres-in-the-world/