Carillion has completed the acquisition of Alfred McAlpine, paying 558p per share, valuing the company at £572M.
Shareholders in Alfred McAlpine will receive 1.08 new Carillion shares and 165.4 in cash for each of their shares.
The combined revenue of the new company will be £4.7bn, closing the gap on market leader Balfour Beatty. Cost savings are estimated to reach £30 million by the end of 2009.
Philip Rogerson, Chairman of Carillion said: "The acquisition of Alfred McAlpine represents a further step in Carillion's development and its successful strategy for sustainable and profitable growth.
"There is an excellent strategic fit between the two companies and the combined group will be one of the UK's leading support services businesses with enhanced capabilities in providing integrated solutions and construction services. We are confident this transaction can deliver significant value for the shareholders of the Enlarged Group."
Roger Urwin, Chairman of Alfred McAlpine said: "Over the past five years we have repositioned Alfred McAlpine into a valuable support services group, with leading positions in a number of growth markets. Carillion's offer recognises this value and gives our shareholders, employees and customers the opportunity to share in the future success of the Enlarged Group."