Insurance shares fell across the board following the decision by the jury in the World Trade Center trial to treat the 09/11 attacks as separate events.
French reinsurer Scor, which covered a portion of Allianz AG's policy, was the worst hit, falling more than 7% because of its possibly insufficient reserves, analysts said.
Allianz said it was disappointed by the verdict and said it would appeal the ruling if necessary.
Scor said it would fully support Allianz's efforts to overturn the verdict.
A separate US appraisals process will now determine the possible extra payout for the insurers involved in the case.
Allianz shares initially fell but then recovered to stand 0.4% higher at 96.10 after it said it expected only an $80m charge if the attacks were seen as two events.
Zurich Financial's stock shed 0.3% while Royal & Sun Alliance was flat, reports said.
Zurich said it may have to pay extra damages of up to $45.7m after the verdict, but that solid reinsurance made it well prepared to pay any extra costs. It said it was considering whether it would appeal the verdict.
Royal & SunAlliance said it was too early to assess the financial impact of the jury's decision, although early estimates said it could mean additional claims of $128m. A company spokesman said the insurer had not yet decided whether to lodge an appeal.
