The transition to 100% BNY Mellon ownership will see Werner Taiber, who was most recently a member of the managing board of Portigon, appointed as CEO, pending regulatory approval.
Financial terms of the deal were not disclosed, but WestLB has over €25bn in AUM and 170 employees.
Mitchell Harris, president of BNY Mellon Investment Management, said: “The completion of this transaction is an important milestone for us.
Germany has one of the most sophisticated investment industries globally and is a key strategic priority for BNY Mellon. Acquiring the remaining 50% of our joint venture is a natural transition for us.”
In his new role Taiber will report to Harris and Curtis Arledge, CEO of BNY Mellon.