28. Tim Cook

Title: CEO, Apple

Country: US

Age: 54

Tim Cook runs the most valuable company on the planet in Apple, which is worth $645 billion. Under Cook's continued direction as CEO, 2015 has been one of the company's best years yet.

Chief among Cook's 2015 successes has been the launch of Apple Music, the company's music-streaming service. The service went live in June and as of October counted 6.5 million paid subscribers and another 8.5 million people using the free trial service. And the iPhone is more popular than ever. At the company's annual fall event, Cook unveiled the iPhone 6s and iPhone 6S Plus, which sold 13 million in the first weekend, shattering previous records. Lately, Cook has been alluding to a forthcoming "massive change in the auto industry," sparking rumors that an Apple Car is on the horizon.

Cook was presented with the Human Rights Campaign Visibility Award this year where he spoke about his deeply personal decision to come out as gay: "I wanted to lend my voice to people who might not be ready to exercise theirs," he said.