Intercompany supply taxation applies where merger orders take retrospective effect, making pre-order transactions taxable in respective companies. When a merger order is given to take effect from an earlier date, supplies between the merging companies during the period from that effective date until the order date are taxable in the hands of the respective companies and must be included in their turnover. During that period the constituent entities are treated as distinct companies for GST purposes, and their registration certificates are cancelled with effect from the date of the merger order.