You’ll need to send your return within 14 days of the effective date of the transaction, even if you do not owe any tax. The effective date is usually the date the transfer completes. It can also be the date the contract is ‘substantially performed’. ‘Substantial performance’ is when one of the following happens, you: pay most of the purchase price — normally 90% of the payment is paid take possession of the property make the first payment of rent for the property