Fortress Investment Group (FIG) announced the retirement of Robert Kauffman on Monday and revealed plans to redeem or buy all of the co-founder’s shares in the company.

Kauffman, who co-founded Fortress in 1998, enjoyed a 15-year stint with the alternative asset manager and most recently oversaw Logan Circle Partners, its long-only fixed-income business.

“It has been a privilege to be able to work with such a talented and motivated group of people,” said Kauffman in a statement. “I am proud to have contributed to the growth of Fortress into what it is today, and I wish the best of success to the entire team.”

New York-based Fortress said it plans to redeem or purchase all of Kauffman’s beneficially owned shares in the company, which total about 51.3 million Class A or equivalent shares as of December 21.

Fortress said it will repurchase Kauffman’s stake at a price equivalent of $3.50 a share and finance the transaction with a combination of cash and a 14-month note. The move will cut Fortress’s dividend-paying share count by about 10%.

“Rob has contributed to Fortress’s evolution from a start-up boutique into one of the industry’s largest and most diverse investment managers. We are grateful to Rob for his years of service, and wish him the best in his future endeavors,” said interim CEO and director Randal Nardone.

Fortress, which has more than $50 billion in assets under management, has seen its stock soar 22% so far this year, almost doubling the S&P 500’s return. The stock was inactive in the premarket on Monday.

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