Canadian security firm GardaWorld has extended its offer after the British company G4S repeatedly rejected its offers.
The offer will remain open for acceptance until Nov. 28, GardaWorld said in a statement on Nov 8.
"We are extending our offer for G4S because, despite its past problems and uncertain future, we believe we can turn the business around," GardaWorld's Chief Executive Stephan Cretier said.
GardaWorld launched a hostile bid in October for larger rival G4S of the UK.
G4S, one of the world's largest private security firms, had rejected GardaWorld's 190 pence per share offer valuing the company at £2.97 billion (US$3.91 billion), calling it "unattractive and opportunistic".
GardaWorld said it currently holds about 1.55 per cent of G4S's issued share capital and received acceptances of about 0.16 per cent.
"An acceptance level of 0.16 per cent is consistent with the derisory level of GardaWorld's offer," the London-listed company said in response to the offer extension.
In early November, G4S also rejected a takeover proposal from U.S. rival Allied Universal Security Services, saying that the highly conditional offer of 210 pence per share significantly undervalues the company.