Environmental consultancy RPS Group, which has offices in Birmingham and Wolverhampton, is to buy Basicshare and its subsidiary companies Martindale Holdings and Burks Green and Partners for up to £21.2 million.
RPS also announced that good trading indicated in the group's AGM statement on May 25 had continued and the board expected to announce strong first half results.
Chief executive Alan Hearne said: "Burks Green will help us sustain both our operating margins and growth."
Burks Green, which provides architectural and engineering advice to the property and infrastructure development sectors, is one of the UK's leading integrated architectural and engineering practices.
The business operates in the UK, Ireland and Poland and has its main office in Newark, Nottinghamshire. It currently employs around 200 staff.
In the year to the end of March the company had revenues of £13.6 million and profit before tax of £3.6 million. Net assets at March 31 were £2.7 million.
Recent clients include Birmingham, Manchester, and Dublin airport authorities, Sainsbury's, Asda, Argos and DSG (formerly Dixons).
RPS said it paid £9.9 million in cash at completion of the acquisition along with 1.47 million new RPS shares valued at £3.2 million.
In addition guaranteed loan notes to the value of £8.1 million were issued.
The Birmingham office of law firm DLA Piper Rudnick Gray Cary acted as lead adviser to RPS, represented by partner Russell Orme and Ceri Williams-Jones. Accountants PKF gave financial advice, led by Malcolm Cooke and Konrad Rutkowski. Eversheds in Birmingham, represented by Stephen Kitts and Evelyn Heron, acted for Burks Green & Partners.