The newly combined entity will be named Redleaf Polhill and will operate from Redleaf's offices in Smithfield, London.
Polhill was founded by Julian Polhill in 1990 and specialises in financial services, while Redleaf has built its presence in the professional and financial services sectors.
Emma Kane, founder and CEO of Redleaf, will become executive chairman of the combined company and Andrew Sharkey, currently a director of Polhill, will become CEO.
Polhill chairman Julian Polhill becomes a non-executive director, as does Redleaf's chairman Ian Rosenblatt.
Redleaf Polhill's combined financial and professional services clients include Close Offshore, Henderson Investment Trusts and Liberum Capital.