Property claims arising from the World Trade Centre (WTC) attacks have now hit the $20bn (£13bn) mark.
This figure is an increase of 22% from the earlier forecast of $16.6bn (£11.1bn).
These figures come from the Insurance Services Office (ISO) which is responsible for adding up losses from the majority of US insurers.
The overall estimate for WTC losses of all types is currently in the region of $40bn (£27bn).
