Form T1198 – Statement of Qualifying Retroactive Lump-Sum Payment is a form you submit to the Canada Revenue Agency (CRA) if you received a lump-sum payment and would like them to complete a special tax calculation that takes into account the unusual nature of this lump-sum payment.
If you answer “Yes”, you will not be able to NETFILE, but if you answer “No”, you will be taxed on your whole lump sum this year.