Leucadia asked for more time to consider a merger.

GATX Corp. officials said they were “astounded” that Leucadia National failed to come through on a definitive merger agreement and gave no assurance that they would grant a seven-day extension sought by the New York holding company. The New York-based investment firm had made a cash offer late last month of $544.8 million, or $40 a share, for GATX, one of the nation’s largest aircraft and rail-car lessors. It appeared that Leucadia had won a bidding war when GATX directors agreed to that offer and set a midnight Tuesday deadline to sign the definitive agreement.