The $4.4 trillion fund giant that's changing money management named a new CEO

F. William McNabb will be stepping down as CEO of Vanguard Group.

He will be replaced in January by Vanguard's current CIO Mortimer J. "Tim" Buckley and transition to chairman next year before also passing that role to Buckley.

McNabb, who joined the company in 1986, became CEO in 2008.

Under his leadership, Vanguard's assets under management have exploded from $1.25 trillion almost threefold to $4.4 trillion.

Vanguard is now the second largest American money manager behind BlackRock.

"As the firm continues to grow, evolve and expand globally, it is the right time for a new leader and the Board is unanimous in its belief that Tim Buckley is the ideal next chief executive for Vanguard," McNabb said in a statement. "I have worked alongside Tim for many years and he brings a strong passion for serving Vanguard clients and crew, a global mindset, and significant leadership experience in all facets of our operations."

Buckley, who is currently chief investment officer, joined the firm in 1991 as an assistant to John Bogle, the legendary investor who was chairman at the time.