Sanlam says Thesis has “a significant presence in the South of England” with £1.2bn under management and a team of 30 investment professionals and their support colleagues.
The deal takes Sanlam’s UK private client discretionary assets under management to £4.2bn.
As part of the deal, Sanlam will acquire Thesis’ private client business, distribution network, direct support teams and Pallant, its Financial Planning business.
Thesis’ offices in Guilford, Lymington, Chichester and Brighton will become part of Sanlam’s regional wealth management network.
Jonathan Polin, Sanlam, UK chief executive, said: “This is an important strategic move for Sanlam in the UK as we look to further enhance our footprint and expertise.
“Both Sanlam and Thesis are fully aligned in their investment philosophy, culture, and a commitment to providing a personalised and dedicated service to clients.
“Our aim is to become the wealth manager of choice for high net worth individuals and their advisers, to be achieved through the delivery of client-centric wealth management excellence.
“The acquisition of Thesis is a significant milestone in that journey.”
The amount paid for Thesis was undisclosed.