The London-based investment manager, formerly owned by Credit Suisse, focuses on discretionary portfolio management for private clients, charities and institutions.
The management team will continue to run the business autonomously and will have the opportunity to become shareholders alongside Bermuda National. The independent directors will also remain on the executive board.
The acquiring firm is a Bermuda-listed financial services holding company created to own financial institutions including banks and investment advisory businesses.
As part of the take-over the firm is developing new branding, but the business model and investment process will remain unchanged.
The deal was first announced in March.
