"We are going to prove the case out of the mouths of the witnesses of the other side," said Barry Ostrager, attorney for Swiss Reinsurance Co.
Ostrager said in his opening statement in Manhattan federal court that leaseholder Larry Silverstein's risk manager, Robert Strachan, negotiated policies in July 2001 that used a broker's form called the Wilprop form, under which the destruction of the trade center was a single event.
Swiss Re and 12 other insurers are at odds with Silverstein over the amount of money the trade center's developers are owed, a figure that could affect the rebuilding schedule at ground zero.
Silverstein and the site's owner, the Port Authority of New York and New Jersey, have argued that he should receive $7 billion, or twice the $3.5 billion insurance policy on the center, because the two planes that flew into the towers 16 minutes apart on Sept. 11, 2001, represent two separate events.
The trial will determine how much Silverstein is entitled to receive in property insurance.
The 13 insurance companies that provided the bulk of the policy contend they issued the policy using the Wilprop form.
Silverstein, who holds a 99-year lease on the property, and downtown development officials have been counting on the larger figure to build the 1,776-foot Freedom Tower, other skyscrapers and cultural buildings on the site within the next decade.
Development officials say failure to collect $7 billion could mean years of construction delays at ground zero.
The trial will focus on whether the insurance companies issued their coverage on the broker's form that would define Sept. 11 as one event or two.
If the jury decides that the form used doesn't define the towers' destruction as one event or two, a second jury would be convened to decide whether one or two attacks brought down the trade center.
Jurors would then determine how much each insurer would have to pay.
A federal appeals court ruled against Silverstein in September, dismissing three insurers from the case by saying their contracts were signed on forms that define Sept. 11 as one event. U.S. District Judge Michael Mukasey later ruled that jurors could be told about that decision.
By Amy Westfeldt