The catastrophic Oklahoma City tornado could leave a damage bill of up to $US3 billion, raising the prospect of another wave of claims for insurance companies.
But locally listed QBE, which makes about a third of its profits in the United States, looks set to avoid most of the financial fallout from the tornado that destroyed entire neighbourhoods on Monday.
Insurance companies have been buffeted by a spate of natural disasters here and overseas in recent years, a trend that has squeezed profits and contributed to a surge in premiums.
QBE's struggling US arm last year made a $US170 million loss after being battered by claims from super storm Sandy and claims from its cropping insurance business.
However, early assessments suggested the financial impact of the Oklahoma tornado, which reportedly killed more than 90 people, would be less severe than the devastating human toll.
Nomura analyst Toby Langley said a preliminary indication of the incident's potential cost was a tornado that had cut a similar path through the city in 1999. "The 1999 event resulted in 49 deaths and damage of $US2.8 billion, of which we estimate insured losses were about $US1.4 billion," he said.
"If we adjust for inflation, it implies insured losses of between $US2.5 [billion] and $US3 billion."
This compares with insured losses from the 2011 Christchurch earthquake of about $US13 billion.
QBE obtains a significant share of its profit in the US market, but Mr Langley said it was unlikely to be heavily exposed to the Oklahoma City disaster.
"Though it is still early on, I think it will be limited by QBE having very low exposure to Oklahoma," he said. "It constitutes less than 1 per cent of their US revenues."
QBE shares fell 1.8 per cent, or 28¢, to $15.40, as part of a sector-wide trend on Tuesday. Analysts said investors were questioning whether the company might be at risk from the event.
In general, tornadoes tend to have a lower financial cost than hurricanes or floods, because their impact is concentrated in a smaller area. But analysts said it was still early in the tornado season and more events such as this could test QBE's provisions for losses.