Stephen Schwarzman

Co-founder and CEO, Blackstone Group

Over the course of three decades, Schwarzman has built the largest manager of alternative investments—a category that includes just about anything that’s not stocks, bonds, or cash—with $365 billion in assets. It’s long been a heavyweight in private equity and more recently has amassed one of the world’s largest real estate portfolios. Oh, and Schwarzman, already the wealthiest man in private equity, is widening the gap with his peers, taking home an estimated $734 million last year, mostly in dividends from his 20 percent stake in the company. 

Paul Singer

Founder and co-CEO, Elliott Management

His New York-based hedge fund oversees about $28 billion of assets and has delivered annualized returns of around 13.5 percent a year since 1977, often by taking activist positions or investing in distressed assets. Singer’s 13-year-long campaign to get Argentina to make good on defaulted debt probably brought him more attention than anything else he’s done. Last year he also shined a spotlight on the merger of two Samsung affiliates that increased family control of the group. In politics he’s one of those billionaires who is courted early by Republican presidential candidates. Singer backed Marco Rubio in the race for the GOP nomination and has not jumped in with Trump since his man dropped out, preferring to spend on congressional races.

MICHAEL PETTIS

Professor, Peking University

A prolific blogger and commentator, Pettis is one of the most prescient and outspoken economists working in China today. The onetime Wall Street banker started warning that China was seeing unsustainable debt growth about a decade ago. His bearish calls seem more prophetic than ever, as rising levels of nonperforming loans stoke worries that the world’s second-largest economy could be headed for a financial crisis. Pettis’s influence stretches beyond markets: His music label, Maybe Mars, is helping China’s underground rock bands get exposure overseas.

Lael Brainard

Governor, U.S. Federal Reserve

Brainard, a former undersecretary for international affairs at the U.S. Department of the Treasury, has been advocating the internationalist line of thought at the Fed. Over the past year she’s repeatedly called attention to the increasingly complex economic and financial linkages that bind the world’s largest economies, to argue that decisions on U.S. interest rates must take into account a broader array of factors than inflationary pressures from tight labor markets at home. In a speech in June she warned that “cross-border financial transmission is likely to be amplified” as long as interest rates set by major central banks remain near zero—a point that the financial shudder caused by the Brexit vote soon confirmed. Brainard’s name comes up often as a possible Treasury secretary should Clinton win the election. 

Robert Gordon

Professor, Northwestern University

A Bloomberg reporter once counted up the references in the footnotes of Fed Chair Janet Yellen’s speeches and found Gordon cited more than any other economist outside the central bank. Gordon has long argued that an exceptional period of U.S. growth from 1870 to 1970 resulted from one-off productivity boosts, such as the invention of the internal combustion engine and the advent of air travel. He says more recent tech innovations, such as the internet and the cell phone, probably won’t have anything like the same positive effect. 

Margrethe Vestager

European Union competition commissioner

The daughter of two Lutheran ministers, Vestager is big on fairness, which you could argue is a prerequisite for her job. She has questioned whether DuPont’s planned takeover of Dow Chemical will hurt farmers by creating monopoly power in seeds, pesticides, or fertilizers and accused Google of using its dominance in phone operating software to advance its other mobile products. The Danish lawmaker has also used competition law to argue that some of the EU’s member states are illegally favoring some companies with tax deals. Last month she ordered Ireland to recoup as much as €13 billion ($14.5 billion) in back taxes from Apple.

Ruth Porat

CFO, Alphabet

Porat, formerly Morgan Stanley’s chief financial officer, has been credited with bringing banker discipline to the geeks and gurus at Google. Alphabet shares have climbed more than 40 percent since Porat landed in Mountain View in May 2015, to the point where the purveyor of Android mobile software now rivals the maker of the iPhone in market capitalization. Of late, even the “moonshot” companies in the Alphabet universe—such as those focused on connected-home devices and high-speed internet service—have begun feeling Porat’s gravitational pull over their budgets. 

MARK ZUCKERBERG

Co-founder and CEO, Facebook

The fifth-richest man in the world (his net worth is up 22 percent this year) continues to dominate social media. His company boasts a portfolio of successful products—Instagram, Messenger, and WhatsApp—in addition to the original. And it’s aced the transition to mobile, the source of 84 percent of Facebook’s ad revenue. So Zuckerberg has breathing room as he tries to figure out virtual reality, for example, or react to the phenomenon of Facebook users streaming live—and sometimes disturbing—news from their phones. 

Travis Kalanick

Co-founder and CEO, Uber

Kalanick has raised $15 billion-plus in debt and equity, making Uber the most valuable startup ever. In addition to courting investors, he’s fighting his way through legal, regulatory, and labor issues that make the technical challenges of a ridesharing network seem comparatively simple. There have been stumbles, as Kalanick’s bias is to run the hurdles fast. Now he’s in a rush to get driverless cars on the road.