(Bloomberg) -- Millennium Management’s Bobby Jain is “stepping back” from his role as co-chief investment officer in one of the biggest overhauls at the top of the $59 billion hedge fund firm.

Founder Izzy Englander, 74, is establishing an office of the CIO, which will include two new co-CIOs and two heads of asset class risk management, he said in a memo to staff on Tuesday evening a copy of which was seen by Bloomberg. Paul Russo, currently global head of equities risk, will become one of the new co-CIOs. His counterpart, who wasn’t identified, will join in May. 

While Millennium sees a constant churn of portfolio managers like many of its multi-strategy peers, an overhaul in the top ranks is extremely rare. Jain joined the firm more than six years ago as co-CIO to work alongside Englander.

“From now until mid-2023, he will support Millennium’s transition to a new organizational structure for the firm’s investment activities,” Englander said in the memo, referring to Jain. “Given the size and scale of our business, as well as our diversification and the prospects for future growth, we have embarked on a deliberate journey.”

A spokesman for the New York-based firm declined to comment. The firm’s capital is deployed by more than 280 investment teams, one of the largest in the industry. 

Scott Rofey, currently head of rates, macro and commodities risk, and Jeff Verschleiser, head of credit and mortgage-backed securities risk, will also join the office of the CIO. Millennium also named Ajay Nagpal its president, a role he will assume along with his current responsibilities as chief operating officer.

Business is booming at Millennium as investors migrate toward multi-strategy hedge funds for their diversified approach to investing and steady returns. The firm and its peers are on the cusp of becoming the most dominant strategy in the $4 trillion industry. Millennium’s hedge fund has gained 10.3% this year through October. 

Millennium has been shifting toward bringing in longer-term client capital, and as part of that effort it will be returning $15 billion to investors at the end of this year. The move is part of the firm’s view that more stable capital is a key tool in attracting and retaining talent.

Jain was previously the global head of Credit Suisse Asset Management. Assets under management almost doubled during his tenure and the firm added many markets and strategies, Englander said in the memo. 

While Jain “isn’t going anywhere just yet,” Englander said he wishes “him the very best in his next chapter.”

©2022 Bloomberg L.P.