IFRS 2 requires an expense to be recognised for the goods or services received by a company. The corresponding entry in the accounting records will either be a liability or an increase in the equity of the company, depending on whether the transaction is to be settled in cash or in equity shares. Goods or services acquired in a share-based payment transaction should be recognised when they are received. In the case of goods, this is obviously the date when this occurs. However, it is often more difficult to determine when services are received. If shares are issued that vest immediately, then it can be assumed that these are in consideration of past services. As a result, the expense should be recognised immediately.
Alternatively, if the share options vest in the future, then it is assumed that the equity instruments relate to future services and recognition is therefore spread over that period.