(Bloomberg) London’s fund industry is bouncing back, and U.S. billionaires Steven A. Cohen and Ken Griffin are grabbing a piece of the action.Griffin’s Citadel and Millennium Management, a hedge fund run by Israel Englander, have bulked up in London, where asset growth is outpacing the U.S. Point72 Asset Management, the family office that oversees Cohen’s wealth, is plotting a return to Europe’s financial hub by year-end, said a person with knowledge of the matter.