Blackstone Group LP bought a minority stake in Marathon Asset Management, a move that will provide the $12.8 billion hedge fund firm with permanent capital and help it to grow.

Marathon, which focuses on distressed-debt investing, will retain its independence and control of the fund, said Andrew Rabinowitz, the firm’s newly appointed president. The terms, which weren’t disclosed, were finalized earlier this week, he said by phone.

The investment “helps with institutionalizing our firm, given that we think Blackstone is the premier alternative asset manager,” Rabinowitz said. “It sends the message that Marathon will be here a very long time.”

The transaction is the fourth of its type for Blackstone, which has raised more than $3 billion to buy stakes of 15 percent to 25 percent in hedge funds. The investment, Rabinowitz said, will help with succession planning and employee retention at Marathon. He said the firm will create a board including one non-voting member from Blackstone, the world’s largest manager of alternative investments and the biggest allocator to hedge funds.

“We have great respect for the sustainable franchise that Marathon has built and their commitment to customization to meet the evolving needs of their growing institutional investor base,” Tom Hill, Blackstone’s vice chairman, said in a statement. “We look forward to partnering with them in the years ahead.”

Senator Startup

Blackstone’s first such deal was in 2014 with Senator Investment Group, a fund it had provided with startup money. In March 2015, it purchased a stake in event-driven hedge fund Solus Alternative Asset Management, helping two of its founders to eventually exit, and in May of last year it bought a stake in Magnetar Capital Partners.

The $2.9 trillion hedge-fund industry may lose about a quarter of its assets in the next year as performance slumps, Tony James, Blackstone’s billionaire president, said last month. Results in its hedge-fund business are better than the industry average, he said, though performance generally remains a cause for concern. He also called out hedge-fund managers for the fees they charge, which are typically 2 percent of assets annually and 20 percent of investment profits -- a structure he said “is hard to justify these days.”

Blackstone had $68.5 billion dedicated to hedge funds as of March 31, and the business produced $244 million in economic income, which includes realized and unrealized gains and losses, in the past year, down 35 percent from the previous 12 months.

New York-based Marathon was founded in 1998 by Louis Hanover and Bruce Richards. The firm’s investments in recent years include the debt of Puerto Rico’s government-owned utility, called Prepa; Norwegian paper maker Norske Skogindustrier ASA; and Ukrainian steelmaker Metinvest BV.