WORLD Trade Center leaseholder Larry Silverstein’s hopes for a quick decision finding that the attacks on Sept. 11 constituted two occurrences rather than one for insurance purposes were dashed yesterday.

Southern District Judge John S. Martin delivered an early victory to the insurance industry, ruling that the term “occurrence” as contemplated by the parties negotiating coverage for the twin towers was ambiguous, and that extrinsic evidence must be considered before deciding how much Mr. Silverstein should be compensated for the destruction.