The purchase could give the expanding Financial Planner access to around 8,500 new clients as new services are offered to clients of Speirs & Jeffrey.
A letter to Speirs & Jeffrey clients, from chief executive Russell Crichton, read: “We expect aspects such as Rathbones’ specialist charities expertise, banking licence and financial planning capability to prove very relevant over the long term and wish to ensure our clients benefit from these.”
It added: “We have thought long and hard about giving up our independent ownership, which has served us well for 112 years, but we firmly believe this is the right thing to do.
“We wish our clients to benefit from Rathbones’ wider range of services.”
The acquisition increased Rathbones’ funds under management by 18% to £44.5bn.
Philip Howell, chief executive of Rathbones said: “From the outset of our engagement, both teams have recognised how compatible they are in culture, investment philosophy and dedication to client service.
“Speirs & Jeffrey represents an ideal strategic, professional and geographic fit with Rathbones and we look forward to working together both to develop our business in Scotland and deliver compelling returns for our shareholders.
“Key to our combined future success will be the principle of putting clients at the forefront of what we do, and we will remain committed to this as we welcome Speirs & Jeffrey into the Group.”
Speirs & Jeffrey chairman, Graham Waddell, said: “This represents a significant milestone for S&J but undoubtedly the right one for our clients and our people.
“The fact that our team will remain intact and that our clients will continue to receive the same exacting standards of personal service, whilst benefitting from the wider resources of Rathbones, fills me with great confidence for the future.”