Based in Newcastle, Blackett Walker specialises in providing holistic financial advice services across the North of England.
The company was founded in 1994 by current directors Richard Blackett and Kevin Walker.
The business has since grown to a team of five financial advisers servicing a client base of more than 1,000.
All support staff will also be retained as part of the acquisition.
The company is also a leader in providing specialist long-term Financial Planning for medical professionals.
John White, CEO of Sanlam UK’s Wealth division, said: “Blackett Walker is a high-quality business with a strong ethos.
“Over the past two decades, Richard and Kevin have built a hugely successful business with the client at its heart.
“Providing high quality service and delivering on clients’ long-term financial ambitions, it very much reflects our approach at Sanlam UK.
“In line with our commitment to expand our regional footprint, this deal will further strengthen our wealth management presence in the North of England.
“I look forward to working with our new colleagues to develop our proposition for current and future clients.”
Richard Blackett, Blackett Walker co-founder, said: “We have always prided ourselves on putting clients first and delivering a high standard of service, so it was important to us to work with a firm with the same approach.
“Sanlam has client service in its DNA and has put significant time and energy into delivering its proposition and digital services to create an impressive client experience.
“We look forward to working with our new colleagues at Sanlam to grow the business in the North of England and continuing to provide a goal-driven service for our clients.”