There were some who hoped that Jane Fraser might be the next chief executive of Barclays. But she always had her eyes on the bigger prize and was lined up as heir apparent to Michael Corbat at Citigroup when she was made president of the Wall Street giant a year ago.

This is a big moment for Wall Street where there have been very few women in senior positions and none have previously reached the top of one of the leading banks. Sallie Krawcheck, who was one of those senior women and was once talked of as a potential chief executive of Citigroup, recently accused Wall Street of going backwards in terms of diversity since the global financial crisis. It had become more white, more male and more middle-aged, she said.