The Billionaire Whisperer Who United Bezos, Buffett and Dimon

Todd Combs spends most of his days reading in a quiet office in Omaha, where he’s an investment manager at Berkshire Hathaway Inc. But one day last year he found himself on a flight to Seattle with an unusual mission: Pitch Jeff Bezos on a bold idea for wringing costs out of the U.S. health-care system.

Two of the biggest corporate chieftains in America—his boss, Warren Buffett, and Jamie Dimon, who runs the largest bank in the country—had already signed on. But they wanted the Amazon.com Inc. chief executive officer on board as well.