Architects SMC Group - which takes in Midlands-based practice SMC Corstorphine & Wright - has snapped up rival Alstop Design in a deal worth #1.8 million.
The takeover involves a cash payment of #900,000 plus the issue of 624,277 new SMC ordinary shares at a price of 144.17p per share.
Alsop, headed by Will Alsop, has offices in London, Toronto, Beijing, Shanghai and Singapore.
Stewart McColl, chief executive of SMC Group, said yesterday: "I am very excited at being able to bring into the SMC Group such a world renowned architect as Will Alsop and his team.
"This acquisition will increase our profile within the international architectural industry significantly increasing our global exposure, particularly to larger, higher margin projects."
Mr Alsop, founder and principal of Alsop, added: "At Alsop, we attract exciting and dynamic design commissions from all around the world.
"Joining the SMC Group will allow us to continue to apply our creative skills within a successfully structured business environment with a strong project implementation record."
Corstorphine & Wright has been involved in a number of major projects in Birmingham, including 45 Church Street and the Chamber of Commerce site at Five Ways. It is also part of the Eastside masterplan team.