Birmingham-based property and construction consultancy DBK Partners has been acquired by RPS Group for £13 million.
Listed RPS, which is headquartered in Oxfordshire, is an international, multidisciplinary consultancy which employs more than 5,000 staff across 125 countries.
The agreement means that Digbeth-based DBK becomes the first project and cost management consultancy to join the group in the UK.
DBK also operates offices in London, Bournemouth and Manchester and employs a total of 120 people.
RPS said: "DBK has enjoyed an incredible decade of growth and employs an extremely talented and enthusiastic workforce.
"We pride ourselves on our long-established client relationships and also successfully attracting new clients from new sectors to our portfolio.
"We have identified a substantial pipeline of opportunity with RPS and we are in a great strategic position to continue to expand."