Wiedman, head of the global client business, was instrumental in driving BlackRock's growth in passive investing.

Asset manager BlackRock's senior executive Mark Wiedman, who was touted to be a potential successor to CEO Larry Fink, is departing the firm, said two sources familiar with the matter.

Wiedman, who joined BlackRock in 2004 to help build the firm’s Financial Markets Advisory Group, was seen as one of a handful of the New York-based money management giant’s executives who could be tapped to fill CEO Larry Fink’s shoes when the 72-year-old co-founder of the firm eventually retires.