Support services group picks up the consultancy as part of plan to triple in size by 2012
Mouchel Parkman has acquired consultant HBS for £46.2m.
HBS, formerly known as Hyder Business Services, was formed in 1999 out of the privatisation of Welsh Water, and was bought by private equity group Terra Firma the following year.
The company works in markets including outsourcing, professional services and property services.
Richard Cuthbert, Mouchel Parkman chief executive said: “This deal represents a significant step, supporting the strategy laid out in our corporate plan – the outcome of which is a business two or three times our current size by 2012.”