GST liability on amalgamation: intra-group supplies during the retrospective period are included in turnover and taxed. Supplies between companies involved in an amalgamation or merger that takes retrospective effect must be included in each company's turnover for the period from the effective date to the order date, and tax on those transactions must be paid; notwithstanding the retrospective order, the companies are treated as distinct for GST purposes until the order date and their registrations are cancelled with effect from the order date.