When George and Jane Russell sold the global investment services firm known as Russell Investments, they formed Threshold Group in 1998 to continue the family’s work as early innovators in impact investing.

Today, it was announced that New York-based Tiedemann Wealth Management, an independent national wealth advisor, has entered into a definitive purchase agreement with Threshold. The acquiring firm has approximately $12 billion in assets under advisement, while Threshold will bring $3.4 billion to the new combined entity.

“More and more, clients are insisting their portfolios align with their values, especially as diversified impact portfolios offer returns which are no longer considered concessionary,” said Eric Russell, who will join Tiedemann’s board of directors.

“Many people, including younger investors, have the expectation to use their financial resources to benefit the greater good by investing in entities focused on making improvements in education, the environment, urban renewal, and more.”

Details of the transaction, expected to close in December, were not disclosed. The Russell family will assume an ownership stake in Tiedemann and will retain a relationship as a client.