Rentokil Initial is facing the prospect of being removed from London's FTSE 100 Index.
According to the Press Association, the demotion could come when the quarterly review of the index takes place, based on market valuations at the close of trading, on Tuesday.
Rentokil's relegation caps a miserable month for the company after its shares tumbled in the wake of problems with its City Link delivery arm.
The poorly performing pest control business could see pre-tax profits significantly below 2007's £142 million.
Chairman Brian McGowan is stepping down after four years at the helm, but reports said leading shareholders had called on the company to find a replacement who can also fill the role of chief executive Doug Flynn.
The Sunday Telegraph said Rentokil's senior independent director Peter Long had been told to find a new executive chairman within weeks.
Changes to the FTSE 100 Index will take effect from the start of trading on Wednesday March 26.