Private equity firm Siguler Guff & Co. and BNY Mellon Asset Management are taking their strategic alliance a step further, with the latter taking a minority stake in the former.

BNY Mellon has taken a 20% interest in Siguler Guff, which has about $8 billion in assets under management and committed capital. Terms of the transaction were not disclosed.

“This transaction formalizes our ties with Siguler Guff and significantly adds to our 'alpha' capabilities,” Ronald O’Hanley, BNY Mellon Asset Management CEO, said. “Siguler Guff's deep private equity and distressed evaluation and selection expertise are very important to BNY Mellon's clients.”

The two firms first teamed up in January, with BNY Mellon agreeing to distribute its products. In May, Siguler Guff took over BNY Mellon’s private equity funds of funds.