CRA Auto-fill (AFR) and capital gains — why the numbers don't match

Auto-fill My Return pulls your T5008 slips into tax software automatically. The problem: the cost-base data it pre-fills is often incomplete, wrong, or missing entirely — and accepting it without review can mean overpaying or triggering a reassessment.

Mis à jour July 2026 · 7 min read
L’essentiel à retenir
  • AFR pre-fills the broker-reported T5008 data, including the unreliable box 20 cost base — it is not a CRA-validated number.
  • Proceeds (box 21) from AFR are reliable and useful for reconciliation. Cost base (box 20) must be replaced with your pooled ACB.
  • Accountants use AFR for completeness checks (did you report every disposition?) — not for the final reported amounts.

What is CRA Auto-fill My Return?

Auto-fill My Return (AFR) is a CRA service that lets certified tax software download your tax slips (T4, T5, T5008, T3, etc.) directly from the CRA’s records. It appears in TaxCycle, ProFile, DT Max, and consumer software like Wealthsimple Tax and TurboTax.

The goal is convenience: instead of typing slip data manually, the software pre-fills it. For most slips (T4 employment income, T5 interest) this works well. For capital gains, it creates a false sense of accuracy.

What AFR pre-fills for capital gains

When you pull AFR, the T5008 slips arrive with these fields:

AFR fieldMaps toReliability
Security descriptionSchedule 3 descriptionUsually reliable
Box 21 — ProceedsSchedule 3 proceedsAlmost always correct
Box 20 — Cost or book valueSchedule 3 ACBOften wrong, blank, or incomplete
CUSIP / account numberIdentificationReliable

The critical gap: AFR does not contain the correct adjusted cost base. It merely echoes whatever the broker filed on the T5008 — which has all the known problems of box 20.

AFR is not a CRA calculation. The CRA does not verify or correct box 20 before making it available through AFR. It’s a pass-through of broker-reported data.

Why AFR numbers differ from what you should report

The discrepancy between AFR data and your correct filing amounts comes from the same structural problems that make box 20 unreliable:

  • Pooling across brokers: You hold RY at Questrade and TD. Each broker files a separate T5008 with only their own cost base. AFR shows both slips with partial cost — neither is the pooled ACB.
  • Return of capital: Annual T3 box 42 distributions reduce ACB. Brokers rarely adjust their reported book value for these. AFR inherits the inflated cost.
  • DRIP purchases: Reinvested dividends add to ACB. Many brokers report a box 20 that doesn’t include these additions — so AFR understates your cost base.
  • FX conversion: Box 20 for USD-traded securities may be in USD or converted at the wrong rate. AFR passes this through as-is.
  • Blank values: When the broker leaves box 20 empty, AFR pre-fills nothing — the software may default to zero cost, creating a phantom gain.

How accountants should use AFR for capital gains

The professional workflow treats AFR as evidence, not truth:

  1. Pull AFR to get a complete list of dispositions the CRA expects to see reported.
  2. Use proceeds for reconciliation — confirm your own calculated proceeds match box 21 for each disposition.
  3. Ignore or override box 20 — replace with the correct pooled ACB from your own records or your client’s capital gains tracking tool.
  4. Document overrides — for each material difference between the AFR cost and your reported ACB, maintain a record showing why (transfers, ROC, pooling, FX).
  5. Completeness check — every T5008 in AFR should have a corresponding Schedule 3 entry (or a documented exclusion reason like a registered-account disposition that was incorrectly slipped).
Never accept AFR cost base without review. Tax software that imports AFR and marks the return "complete" without ACB validation is creating filing risk — either for the taxpayer (overpayment) or the preparer (reassessment liability).

Reconciling AFR against your data

A proper AFR reconciliation produces a clear trail:

CheckSource A (AFR)Source B (your records)Action
Disposition exists?T5008 slip presentTrade in historyMatch — report on S3
Proceeds match?Box 21Your calculated proceedsUse your figure; flag if >$10 difference
Cost base match?Box 20Your pooled ACBAlways use your ACB; document the override
Missing from AFR?Trade in historyStill report — broker may have filed late
Extra in AFR?Slip presentNo matching tradeInvestigate — possibly a different account or an error

A note for DIY filers using Wealthsimple Tax or TurboTax

Consumer tax software also uses AFR. When you connect your CRA account and import slips, the same T5008 data pre-fills. The risk is that consumer software makes it easy to simply accept and submit without reviewing cost base.

If you have any of the following, the AFR cost base is likely wrong:

  • The same stock held at more than one brokerage
  • ETFs that pay return of capital (most Canadian ETFs do)
  • DRIP reinvestments in non-registered accounts
  • Shares transferred between brokers
  • US-dollar trades (the FX conversion on cost must use the settlement-date BoC rate)

Review every pre-filled cost base before submitting. Replacing it with the correct ACB can mean the difference between overpaying thousands in tax and filing correctly.

Questions fréquentes

Is CRA Auto-fill My Return data accurate for capital gains?

Proceeds (box 21) are almost always accurate. Cost base (box 20) is frequently wrong, blank, or incomplete — because AFR merely echoes what brokers reported on the T5008, without any CRA verification or correction.

Should I just accept what AFR pre-fills for my T5008 slips?

Accept the proceeds, but always review and override the cost base. The pre-filled cost is the broker’s book value, which ignores pooling, return of capital, DRIP, FX, and transfers. Replace it with your own calculated ACB.

What does the CRA do if my Schedule 3 amounts differ from AFR data?

The CRA uses AFR/T5008 data for automated matching. They flag missing dispositions and large unexplained proceeds differences. Overriding the cost base with a higher (correct) ACB is normal and expected — just keep supporting records.

Can my accountant use AFR to verify my capital gains report?

Yes — AFR is excellent for completeness checks (confirming every disposition is reported). But the cost base must come from an independent source like trade history, not from AFR pre-fills.

Continuer la lecture
Why your T5008 box 20 is wrongHow to import capital gains into tax softwareHow to report stock sales to the CRAWhat is adjusted cost base?

Information éducative, pas un conseil fiscal. Les règles résumées ici peuvent changer et ne s'appliquent pas nécessairement à votre situation — confirmez toujours vos déclarations de gains en capital avec un comptable canadien qualifié.

Ne constitue pas un conseil fiscal ou juridique. Confirmez toujours vos déclarations de gains en capital avec un comptable qualifié. · Fait avec amour au Canada 🇨🇦
© 2026 Sched3