Template:M summ IETA 5.1(d)
In its yen to over-specify and state the obvious, the IETA Master Agreement almost trips itself up: obviously the Transfer can’t be complete until the Allowances have arrived in the Receiving Party’s Holding Account (and, for the record, the no encumbrances condition of Clause 5.3 is complied with); and it is true the risk of loss of the actually transferred Period Traded Allowances only shifts at that point, but do note the other risks associated with the generic class of Allowances being sold: economic ones, market value, abandonment of scheme risks and so on — transfer at the moment of trade.
This is something that practitioners in the carbon market seem confused about.