Shares in Interserve fell on Wednesday after the UK Cabinet Office said it was setting up a team to monitor government outsourcing companies following the collapse of Carillion this week.
Carillion, which issued a series of profit warnings last year, was put into liquidation on Monday, raising questions about why those warnings from a key government services provider were ignored.
Interserve, which issued a profit warning in September, has been put on the Cabinet Office team's watch list. The FTSE 250-listed company employs 25,000 in the UK and around 80,000 worldwide.
The company's shares fell as much as 14% in opening trade, despite last week reporting in a trading update that its 2017 results would be in line with expectations.