A US Federal Appeals Court has delivered a mixed verdict to World Trade Centre leaseholder Larry Silverstein, meaning he will be able to collect $1.1 billion ($1.45 billion) from some insurers while others will pay only on a single-event basis.

The ruling upheld two jury verdicts which required some insurers to treat the September 11 terrorist attacks as two separate events but allowed others to treat them as a single event due to the wordings of their policies.

The ruling requires additional damages from insurers including Allianz, Zurich American Insurance and Travelers Indemnity. Others – including AIG’s Lexington unit, Swiss Re and Lloyd’s – will only have to pay on a single-event basis.