Jack Bogle launched Vanguard Group Inc. with little more than a college thesis. When Jack Brennan took over, the company had less than half of the assets of heavyweight Fidelity Investments. And even Bill McNabb, who rose to the top job at Vanguard in 2008, could still pitch the company's index funds as an alternative to Wall Street's traditional offerings.

Mortimer J. "Tim" Buckley, who became Vanguard's fourth CEO this week after more than two decades with the company, is the first to take over the mutual fund giant when it is no longer an outsider. In the first 11 months of 2017, Vanguard took in more than six times as much as Fidelity, American Funds, T. Rowe Price and Pimco combined. (Blackrock, which is dominant in the exchange-traded fund business, is the only other asset-management firm that has rivalled Vanguard's success in recent years.)

Bloomberg