G4S chief executive Nick Buckles told British MPs on Tuesday he regrets the security company ever took on the Olympic security contract, as it has become a "humiliating shambles".
The company may lose £50 million from the £284 million contract because it cannot supply enough security guards.
Mr Buckles told MPs on Tuesday that the military and the police would be reimbursed for providing personnel to plug the shortfall.
But he said G4S planned to keep its £57 million management fee. Mr Buckles said it would retain the fee because G4S expected "to deliver a significant amount of staff" .
The BBC reports G4S has been under fire since it emerged last week that 3500 extra military personnel have had to be deployed to meet a shortfall in trained security guards for the Games.
Police have also helped fill gaps left by G4S.
Cabinet ministers insist the security of the Games will not be compromised.
Mr Buckles said the cost of accommodation for military personnel called in to help would be covered and bonuses would be paid to them if this was deemed appropriate.
He said he was "very sorry" for what had happened.
Mr Buckles said it was on 11 July that he realised the contract would not be delivered - the same day Home Secretary Theresa May says she was informed of the problems.
G4S had been contracted to supply about 10,000 personnel.