Allianz could be exposed to claims of at least $100m linked to the AirAsia jet missing off the Indonesian coast with 162 people on board.
This would be the third major airline accident Allianz has been exposed to this year.
Allianz said it was the lead reinsurer on the flight. It was also the main reinsurer to Malaysia Airlines flight MH370 which disappeared over the Indian Ocean in March, as well as to flight MH17, shot down in July while flying over Ukraine.
In an emailed statement Allianz confirmed it had lead the provision of aviation hull and liability cover.
"It is much too early to comment on reports of this incident except to say that our thoughts and prayers are with all those affected by this missing flight," it added.
One aircraft insurance broker estimated total costs would depend on liabilities for passengers and could be between $100-$200m, including around $45m for the plane.
Not all the costs would be borne by Allianz but the insurer declined to comment on the extent of its exposure, or to identify others exposed to the missing Airbus A320-200.
Aviation incidents accounted for four of the top 10 major insurance losses not linked to natural catastrophes in the first eight months of 2014, putting pressure on aviation claims that are already rising due to the use of expensive materials and demanding safety regulation, an Allianz report said.
As with the two Malaysia Airlines crashes, Allianz and its co-insurers will have to foot the bill for the cost of the missing aircraft, as well as for payments due to the relatives of passengers aboard the flight.
The Airbus 320 sells for an average price of $94m, according to Airbus's website. However, according to the age of the aircraft, the hull is likely to be insured for a lower sum.
For passenger liability, an international agreement called the Montreal Convention caps initial payouts at around $165,000 per passenger at current exchange rates, or a total of about $27m for the 162 passengers aboard the AirAsia flight.
But if the airline is found to have been at fault, such as through pilot error, claims could be much higher.
In a recent aviation safety study, Allianz said there are currently fewer than two passenger deaths for every 100 million passengers on commercial flights, compared with 133 deaths for every 100 million in the 1960s.