NEW YORK (Bloomberg) ? Larry Silverstein, leaseholder of the World Trade Center site, should be paid up to twice the limit of some of his insurance policies covering the property destroyed in the September 11, 2001, terror attacks and only once the maximum on other contracts, a US appeals court ruled.

The decision by the New York-based court today permits Swiss Reinsurance Co., a Lloyds of London syndicate and seven other insurers to treat two plane crashes that destroyed the buildings as a single loss claim. St. Paul Travelers Cos., Allianz SE and seven other insurers have to pay Silverstein for two losses because each plane attack can be counted as a separate event under the wording of their policies, the court said.

The ruling, which affirmed two jury verdicts, leaves a maximum payout of $4.6 billion toward the redevelopment of Manhattan?s Ground Zero, some of which will go to Silverstein, and some to the site owner, the Port Authority of New York and New Jersey. Both sides claimed US District Court Judge Michael Mukasey erred in his handling of two 2004 trials over Silverstein?s claims and sought reversals of rulings related to coverage of the $3.2 billion lease of the trade center.

?These forms were designed with different interests in mind and, not surprisingly, yielded different results,? wrote Judge John Walker for the unanimous appeals court in New York. ?Chief Judge Mukasey did a masterful job shepherding this complex, hotly contested case through both phases of a lengthy jury trial.?

Walker said that determining how much the insurers must pay was complicated because only one insurer had issued a final policy on the World Trade Center at the time of the attacks. Silverstein was in negotiations with the others, which provided temporary coverage under insurance binders.

The verdicts were ?a reflection of the fact that the parties were at various stages of negotiating coverage when the two hijacked airplanes destroyed the WTC?, Walker wrote.

Silverstein originally sued the insurers a month after the attack, claiming they all owed him $7 billion, or twice the policy limit, because each jet counted as a distinct event.

The first ruling, in May of 2004, found that Swiss Re, Silverstein?s lead insurer with 24 percent of the $3.5 billion policy, and the others in that phase had agreed to an interim policy form, known as the ?WilProp? form. It had language that defined ?occurrence? to mean all losses that can be attributed to ?a series of similar causes?. The judges previously ruled that that means what happened on September 11 was a single event under those forms.

The Wilprop form was used by Silverstein?s insurance broker, Willis Holdings Ltd., to solicit coverage. Besides Lloyds and Swiss Re, those insurers include Chubb Corp. and Employers Insurance of Wausau.

The second verdict involved nine insurers who were found not to have the same explicit language in their preliminary contracts. In this case, a different jury found that in the absence of such language, the insurers were required to treat each crash as a separate occurrence.

Besides St. Paul Travelers and Allianz, that phase also included Zurich American Insurance Co. and Industrial Risk Insurers, which Swiss Re has since bought from General Electric Co.

The case is SR International Business Insurance Co. Ltd. v World Trade Center Properties LLC et al, 01-CIV-9291.