33. Michael Bloomberg

Title: CEO, Bloomberg LP

Country: US

Age: 73

Michael Bloomberg is back — and he’s making sure his presence is known. After leaving Bloomberg LP, the financial data and media giant that he founded in 1981, and spending 12 years as mayor of New York City, Bloomberg was expected to devote his time to giving away his immense fortune, which stands at $42 billion. Instead, Bloomberg made waves by returning to the helm of his company in 2014, effectively ousting CEO Dan Doctoroff.

Bloomberg didn't return as a figurehead — he immediately began shaking up the company. The newsroom saw layoffs, a management overhaul, and a website relaunch — as well as the exits of news head Matthew Winkler and top digital editor Joshua Topolsky — as Bloomberg flexed his authority over the company. 

The former mayor has had less luck asserting his vision over public policy. Though he effectively instituted a smoking ban in New York City, his efforts to eradicate big sodas fizzled out in the courts last year. He has pledged $50 million to combat the NRA, though little progress has been made on gun control thus far.