NEW YORK (Reuters) - BlackRock Inc, the world’s largest asset manager, is reshuffling some of its top regional executives and placing new leadership at the head of its lucrative alternatives business, according to a memo on Tuesday.

A man walks next to a BlackRock sign pictured in the Manhattan borough of New York, October 11, 2015. REUTERS/Eduardo Munoz

Mark McCombe, who has already taken over managing people who used to report directly to Chief Executive Larry Fink and President Rob Kapito, is dropping his role as head of BlackRock’s alternative investing business line to focus exclusively on leading the Americas region, according to the memo, a copy of which was seen by Reuters.

Replacing McCombe as head of the BlackRock Alternative Investors division is David Blumer, a former Credit Suisse Group AG veteran who joined BlackRock about four years ago and most recently headed the company’s Europe, Middle East and Africa (EMEA) region, the memo said.

Rachel Lord is taking over that region, according to the memo, bringing a senior executive whose primary focus has been iShares exchange-traded funds (ETFs) into a more prominent role in that market. Stephen Cohen, who has focused on the rapidly growing bond ETF business, is assuming the role as head of EMEA iShares, according to the memo.

The moves bring fresh blood into the top leadership ranks at BlackRock. One of BlackRock’s founders in 1988, Fink has not publicly named a successor, but McCombe is among a small group tipped as possibilities, including Kapito, Chief Operating Officer Rob Goldstein and Mark Wiedman, the global head of iShares.

BlackRock has $5.7 trillion in assets under management. Index-tracking ETFs, once considered an industry backwater, are now responsible for the lion’s share of the billions in cash BlackRock pulls in annually and a source of consternation to traditionalist stock pickers who typically charge higher fees.

Earlier this year, BlackRock overhauled its actively managed equities business, cutting jobs, dropping fees and relying more on computers to pick stocks.

Alternatives, meanwhile, range from hedge funds to real estate and infrastructure projects like wind and solar farms. The unit represents 2 percent of BlackRock’s assets but an outsized 6 percent of fees. Fink has made growing that business a priority, and the unit has attracted cash this year. But the space has grown increasingly competitive as institutional clients balk at locking up money and paying high fees for results that can be lackluster.

A Wharton-educated former HSBC Holdings Plc Hong Kong chief executive, McCombe has hop-scotched the globe for BlackRock since the company announced his appointment in 2011.

He joined as chairman of BlackRock’s smallest global region, Asia Pacific and is based now in San Francisco, where many of the company’s data-driven quantitative investors involved in the stock-picking overhaul are based.

“We regularly review, with the Board, leadership and succession planning for all of our businesses and seek to ensure we are developing leaders with broad experience across the entire firm,” Fink and Kapito said in the note.

The changes take effect immediately, they said.