BlackRock Inc. revamped its management on Thursday, greatly expanding the responsibilities of two rising stars on the list of potential successors to Chief Executive Officer Laurence D. Fink.

The world’s largest asset manager is putting Mark Wiedman, who oversees the iShares exchange-traded funds, in charge of a new unit combining the ETF and index-investing business effective Thursday, according to an internal memo provided by BlackRock.
Mark McCombe, who co-heads alternatives, will take on a newly created role as head of the Americas starting Jan. 1.

Wiedman, who has been responsible for $1.2 trillion at iShares, will now oversee almost $3.2 trillion of BlackRock’s $5.1 trillion in assets.

Fink, 64, and President Robert Kapito, 58, have awarded promotions via at least three other reorganizations in recent years as the fund giant grooms its next generation of leaders. The New York-based firm added eight members to its global executive committee and shook up its investment unit in 2012 to improve returns. Two years later it gave at least 10 senior executives new roles, including promoting Rob Goldstein to chief operating officer. This January, the firm named Rich Kushel to head multiasset strategies and Tim Webb to oversee global fixed income.

‘Fresh Look’

“We periodically step back and take a fresh look at the firm to determine how we should evolve our organization in anticipation of changing market dynamics and client needs,” Fink and Kapito wrote in today’s memo. “We also look to further develop our leadership team -- asking leaders to take new or expanded roles.”

Both Wiedman, 45, and McCombe, 50, have quickly risen through the ranks. Fink promoted Wiedman from head of corporate strategy to his first major management role in 2011 as head of the global iShares business.

By merging iShares with beta strategies, BlackRock can more easily discuss with clients how ETFs and other types of index products may fit into a portfolio. The merger comes amid other moves at the company’s index division, which had about $1.9 trillion as of Sept. 30. Amy Schioldager, who oversees portfolio management of stock index products, plans to retire early next year and stay on as a senior adviser, Bloomberg reported in April.

This article was provided by Bloomberg.