Some $475m separated the Norwegian Cruise Lines from Prestige Cruise Holdings’ bargaining positions when the two firms’ chief executives began merger talks early this summer but it took no more than a potential $50m sweetener to move smaller Prestige to “yes”.

New securities filings by Norwegian, the smaller of the three major New York-listed cruise lines, reveal new details about the merger agreement unveiled last month and the finances of privately-owned Prestige.

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