A Fortune investigation reveals sophisticated—and often controversial—tactics that have made Elliott Management the world's biggest, most successful activist fund. : In the summer of 2015, the activist hedge fund founded by Paul Singer had gone to war in the Republic of Samsung to stop the South Korean conglomerate from going through with what Singer considered to be an unfair deal. Elliott Management, the hedge fund that Singer launched 40 years ago and still leads today, was then a large investor in Samsung’s construction division.