McNabb, 50, has been with Vanguard since 1986. He currently serves as a managing director overseeing Vanguard's institutional and international businesses, with about $700 billion in assets under management.

He will begin his role as president and director on March 1 and will succeed chief executive officer John Brennan within a year.

Brennan, 53, has served at Vanguard as president since 1989 and CEO since 1996. He will remain board chairman.

Valley Forge-based Vanguard manages $1.25 trillion in mutual fund assets, including more than $350 billion in employer-sponsored retirement plans.