The Mather Group (TMG), an Illinois-based wealth manager, has acquired local multifamily office Astraeus Advisers, marking the launch of a new family office unit.

The new division will offer financial planning, tax advisory, investment management, concierge and lifestyle services.

It will tend to 18 families, having over $5bn in combined assets under advisement.

The acquisition of Astraeus adds over $1bn in assets to TMG’s portfolio.

Financial terms of the transaction were not disclosed.

Astraeus president and founder Chris Yannella said: “Very few multifamily offices provide comprehensive, technology-driven services like The Mather Group.

“I was also drawn to their fiduciary-only approach and refusal to accept private equity backing.”

The latest deal follows TMG’s purchase of Berman Investment Advisors, a California-based financial planning firm with more than $1bn in assets.

TMG founding partner Stewart Mather said: “Acquiring Berman Investment Advisors and Astraeus Advisers, two well respected multifamily offices, has allowed us to build TMG Family Office on a proven, strong foundation.

“The two firms have been working with families of significant wealth for decades and will bring invaluable experience to this new business unit.”

TMG currently has more than $7bn in assets under advisement and employs 60 staff.

Its offices are located in Chicago, which serves as its base, along with Houston, Dallas, Atlanta and the San Francisco Bay Area.