A slip and a return disagree. Which one is wrong?

Reviewed by EverStone CPA · August 2026

Quick answer: A mismatch letter means the CRA holds a slip — a T4, T5 or similar — that does not agree with a return, and it will generally assess based on the slip unless something is corrected. The fix depends on which side is wrong: a wrong slip gets amended by whoever issued it; a wrong return gets adjusted. For owner-managers who issue their own slips, both sides are yours — which is inconvenient and also means you can actually fix it.

Why the slip usually wins by default

Slips are third-party data; returns are self-reported. When they disagree, the system’s default is to trust the slip and adjust the return. That default is rebuttable — but only by correcting whichever document is actually wrong, through its own correction channel. Arguing with the letter while both documents stand unchanged fixes nothing.

The owner-manager version

When your corporation issued the slip, the mismatch is an internal bookkeeping question wearing a CRA envelope: did the slip report what was actually paid, and did the personal return report what the slip says? The usual culprits are salary accrued but reported inconsistently, a shareholder loan reclassified late, or an amended amount that only got amended on one side.

Fix it in the right order

Find the true number first — from the ledger, not from either document.
Correct the wrong document — amended slip through the slip system, or an adjustment to the return. Not a letter explaining; a correction filed.
Then respond to the letter, quoting the reference number, stating what was corrected and where.

Done in that order, mismatches close quietly. Done as correspondence-first, they generate reassessments that then need objections — the expensive path to the same destination.

Book a free consultation Email us your question

Fastest first step: email what you’re facing to info@everstonecpa.com — reply within one business day, and we book the consult from there.

General information, not tax advice. The document in your hand and its own dates govern.

Common questions

The slip is from someone else and it is wrong. What now?+

Ask the issuer for an amended slip — that is routine and they have done it before. If they refuse or vanish, respond to the letter with your evidence of the true amount; the default trust in slips is rebuttable with records.

Can I just pay the difference and move on?+

You can accept the assessment — sometimes that is rational for small amounts. But if the slip is wrong, paying leaves wrong data standing, and it tends to come back on the next year too. Fixing the document usually costs less than it seems.

Will this trigger a review of everything else?+

A mismatch letter is a matching event, not a case opening. What escalates matters is inconsistency left standing — which is an argument for the correction-first order, not against responding.

We issued the slip ourselves. How fast can this be fixed?+

Amended slips are filed through the same channel as originals and the correction is quick once the true number is established from the books. Email both documents and the ledger extract to info@everstonecpa.com and we will tell you which side to fix.

Two documents, one truth

Email both sides of the mismatch — we identify which to fix and file the correction.

Email us — info@everstonecpa.com Or book directly