Shares in Balfour Beatty plunged more than 20 per cent in early morning trading, after it issued its fifth profit warning this year.
The company said its construction business is likely to show a £75m profit shortfall at the end of the year, but added that trading for the rest of the group remained in line with expectations.
Shares fell to 182p, a 20 per cent drop from Friday's closing price of 224.80 per cent.
The company, subject of a failed merger bid with Carillion earlier this year, has appointed auditor KPMG to conduct an independent review of its construction arm Construction Services UK.
A company statement said:
The review will focus on commercial controls, on 'cost to complete' and contract value forecasting and reporting at project level.
Balfour Beatty also revealed that its search for a new CEO was at an "advanced stage". Former chief executive Andrew McNaughton stepped down in May following a third profit warning in three months. It issued another one in July.
Earlier this month Balfour agreed the £820m sale of US design consultancy Parsons Brinckerhoff to Canadian firm WSP global, a move that thwarted a potential £3bn mega-merger with Carillion.