A notional assessment is an assessment the Canada Revenue Agency raises when a taxpayer has not filed a required return. Acting under its authority to assess tax payable, the CRA estimates income and issues an assessment based on the information available to it, which is often higher than the taxpayer's actual liability because available deductions and credits are not reflected.
A notional assessment is legally valid and enforceable until displaced. The usual remedy is to file the outstanding return, which the CRA then processes and reassesses to the correct figures. Where the filing deadline for an objection has passed, late-filing relief or an extension application may be needed to dispute the resulting balance.