The first name who come in mind to answer this question would probably be the powerful JP Margan Chase or Bank of America. They both have been overtaken long ago by the Chinese giants such as ICBC, China Construction Bank and Agricultural Bank of China in the list of the largest banks in terms of assets. However, even these Chinese Bank, with their hundreds of millions of customers, are not the first banks of the world in terme of the number of users.
The winner is Tencent. The WeChat messaging owner exceeds all banks, even Chinese, in number of customers. A revealing podium of the transformations in finance, with the emergence of actors from the web or mobile. Today Tencent has no less than 600 millions customers as for ICBC its nearest rival they count only 490 millions.
WeChat, the multi-purpose mobile messenger with 980 million active users a month, also has its payment service WeChat Pay fully integrated. Everybody tries to copy it, even the American giant Facebook gets in with his payment between individuals on Messenger. WeChat Pay has become so inescapable that traditional payment players, from terminal manufacturers to Western banks, all fighting to sign partnerships for Chinese tourists
Of course, Tencent is not quite a bank even though it weighs in on the stock market some 470 billion dollars, it is rather a payment institution. That said, this podium is indicative of ongoing transformations in finance.