LONDON (AP) — Standard & Poor's has downgraded its credit rating for the U.K.-based security firm G4S by one notch to BBB-, citing the company's poor handling of its contract with the London Olympics.

G4S fell short of fulfilling its contractual obligation to provide trained personnel to the Olympics. In its downgrade statement on Monday, S&P notes G4S will have to pay the costs associated with providing extra military and police personnel during the games.

It says G4S' efforts to improve its financial performance since the Olympics will only be felt in the medium term.

The agency says G4S's reputation had suffered because of the "high profile" failure but that the company continues to win new contracts despite the setbacks.