The £9m cash incentive and share deal has already been shared out among the practice's existing partners.
Chairman Mike Nightingale believes the deal will give the practice the necessary financial backing to bid for more PFI healthcare projects, as well as expanding into Australia, South Africa and the USA.
Nightingale said: "Our aim is to be recognised as the world's leading architect in the healthcare field."
The firm also hopes to double the size of its Brighton office and expand in the north of England.
Nightingale has appointed Simon Smith as financial controller, a new position created as part of the restructuring. Smith joins from stationery firm the Really Good Card Company.
Alistair Cory has rejoined the practice as development directorafter leaving last year to join construction manager Mace.
Tribal specialised in the education, healthcare and local government sectors. In March, the group bought health planning management consultant Secta.