Jesse Cohn, 34
Back when he was a teenage computer camp geek in the 1990s, Jesse Cohn taught himself to program and earned an advanced IT certification issued by a company called Novell. So when some 15 years later—as a portfolio manager at one of the most influential activist hedge funds—Cohn launched a hostile bid to acquire Novell, he mentioned the accolade in his letter to the board. Novell soon sold at an even higher price, netting a windfall for Elliott, the $25 billion hedge fund run by Paul Singer, which owned a big block of the stock. A tech-savvy and surefooted negotiator, Cohn has since led more than 30 shareholder campaigns against the likes of Compuware, BMC Software, and lately EMC, becoming one of the most powerful and effective activists in the finance industry. Elliott has found his activist approach so lucrative—often doubling or tripling the firm’s original investments—that the fund invented a new role for Cohn dedicated to it.