Investment bank Evolution, which is the subject of a bid approach from South African financial group Investec, said it had sealed the takeover of BNP Paribas Private Investment Management.
Evolution had said last month that it was in talks over buying the unit, as part of its plans to grow its wealth management arm.
Evolution said on Monday that the acquisition would bring some 1.8 billion pounds in assets under management to its Williams de Broe wealth management arm.
"The acquisition furthers our aim to grow assets under management to £10bn in the medium term and we welcome the clients of PIM to Williams de Broë and its growing franchise," Evolution Chief Executive Alex Snow said in a statement.
Analysts have said that Evolution's wealth management business itself may be one of the reasons why it has attracted the attentions of Investec.
Investec, which has been boosting its asset management business to diversify beyond lending, said this month that its preliminary approach to Evolution was made "subject to obtaining a unanimous recommendation from the Evolution board and the satisfactory completion of due diligence."