The phrase “Go west, young man” originates from America’s rapid expansion during the 19th century. Many European investment banks have turned their eye to Wall Street over the years, and attempted their own versions of “going west”.
The reason for this is simple: the US has the deepest and most liquid capital markets in the world. This is one of the reasons why US investment banks consistently outgun their European counterparts. Many European banks have tried, but never quite succeeded, in getting to the top table.