The partners have bought out 3i’s shareholding for a reported £70m now and £40m later, and increased share ownership from 80 to all 140 partners.
3i bought a 40% stake in 2007.
The practice will now be led by a new partnership board comprising Lord (Norman) Foster as chairman, Stefan Behling, Grant Brooker, Nigel Dancey, Spencer de Grey, Gerard Evenden, Luke Fox, David Nelson, Matthew Streets and David Summerfield.
Lord Foster said: “We have enjoyed an excellent relationship with 3i over the last seven years. They have helped us on a number of fronts including strategy, investment in research, governance, planning, accessing new markets and bringing best practice to the way we manage our business. The practice is more international, offers a greater diversity of services and is more exciting than ever before. Today we look forward to continuing to build on our success, but now as a company that is fully owned by its partners and which keeps design excellence at the forefront of everything we do.”
3i managing partner Alan Giddins added: “We are proud to have participated in the transition of Foster + Partners’ ownership to a long-term partnership model, as well as supported the company’s growth, geographic expansion and service diversification. Foster + Partners has built a strong platform and has an unrivalled global brand in its sector.”