Pedestrians walk with umbrellas in front of BlackRock Inc offices in New York, U.S.

BlackRock is undergoing a large reorganization, shuffling the roles of about 20 directors and aiming to take its alternative investments business "to the next level," according to an internal memo.

The world's largest asset manager, with $6 trillion in assets under management, is increasingly betting on nontraditional investments including private equity, hedge funds, commodities and real estate. The firm added at least four new roles to its alternative business unit that will combine the sales and investment teams, according to an internal memo circulated Tuesday.

"The dramatic changes transforming both the markets and our industry ... represent the biggest opportunity in a decade to differentiate BlackRock – but only if we are willing to be bold and decisive," the firm's CEO, Larry Fink, and its president, Rob Kapito, said in Tuesday's memo.

Edwin Conway, who served as global head of the firm's institutional client business, will become global head of BlackRock Alternative Investors. Jim Barry, who has led the firm's real estate and infrastructure groups, will become chief investment officer of the alternative unit, the memo said.

BlackRock is already making waves in the alternatives sector. It is reportedly raising around $10 billion for its private equity fund to replicate the investment approach of Warren Buffett's Berkshire Hathaway. The Wall Street giant in February also partnered with private equity firm KKR to invest $4 billion in the Abu Dhabi National Oil Co., becoming the first institutional investors joining forces with a national oil producer in the Middle East.

The reorganization comes as the New York-based firm and other asset managers are working through major shifts in their business. BlackRock has seen a slowdown in profits amid the continuing fee war among money managers. Fourth-quarter revenue fell short of expectations and its assets under management dropped 5 percent, to $5.98 trillion, over the last 12 months.

BlackRock revealed in January that it plans to cut 500 jobs, or 3 percent of its workforce this year.

The moves announced Tuesday are part of the firm's effort to get closer to clients "to deepen our relationships with them," the memo said.

"We are incredibly excited about these changes. They show our commitment to constant reinvention and to the ongoing development of our senior leaders. They are also designed to reinvigorate our approach at every level of the firm – and with every employee – at a critical time," Fink and Kapito said in the memo.