What harvesting actually does (and doesn't do)
Tax-loss harvesting means selling investments at a loss in a taxable account so the realized losses offset realized capital gains from the same year. If the losses exceed the gains, the excess can be carried back up to 3 years or forward indefinitely to offset gains in other years. There is no cap on how much you can harvest. What it doesn't do: create money out of nothing. A harvested loss is a real sale at a real loss — the tax benefit softens it, it doesn't erase it. And it only works in non-registered (taxable) accounts: gains and losses inside your RRSP, TFSA, or FHSA aren't reported to the CRA at all, so there is nothing to harvest there.
Step 1: total your 2026 realized gains
Before selling anything, know the number you're offsetting. Add up every capital gain you actually realized in 2026 — stocks sold, funds sold, property dispositions. Unrealized gains (things you still hold) don't count yet. If you have no realized gains, harvesting still has value: losses carry back 3 years against past gains or forward indefinitely against future ones. Your unused capital losses available to carry forward appear on each year's CRA Notice of Assessment — keep that number handy alongside your 2026 gains total.
Step 2: inventory your unrealized losers
List every holding in your taxable account currently worth less than you paid for it, with the size of the unrealized loss on each. Rank them by loss size. The harvesting decision then runs: which losers, when sold, would cover your Step 1 gains total without overshooting wildly? Overshooting is fine (the excess carries), but the cleanest harvest covers the gains with the least disruption to your portfolio.
Step 3: the 61-day window check (the superficial loss rule)
This is the step that sinks most amateur harvests. The CRA's superficial loss rule denies the capital loss if you — or an affiliated person — buy the same or identical property within 30 calendar days before through 30 calendar days after the settlement date of your sale. That's a 61-day window. "Affiliated person" is wider than most people think: it includes your spouse and your controlled corporation, and it includes your own RRSP and TFSA. The classic trap: selling a stock at a loss in your taxable account, then buying the same stock inside your TFSA a week later. Even though the accounts are separate, the CRA treats both as controlled by you — the loss is denied.
Two legitimate ways through the window:
- Wait 31 days before repurchasing the same security. Simple, but you're out of the market in that position for a month.
- Swap immediately into a similar but non-identical security. Sell one provider's TSX Composite ETF and buy another provider's broad Canadian market ETF the same day. You keep equivalent market exposure without tripping the rule — the properties must not be identical.
Step 4: sell before the settlement deadline
The CRA looks at the settlement date, not the trade date. To claim a loss for the 2026 tax year, the trade must settle by December 31. Because stock trades in Canada settle on a T+1 basis, the sell order generally needs to be placed at least one business day before the end of the year — selling on December 31 itself settles in January and misses the year. In practice the margin is thinner than that: brokerages publish their own year-end trading deadlines each December, and the published date is the one to work to, not the last trading day. Most harvesting happens in the December 15–30 window precisely because the final days get congested. Check your brokerage's deadline now, and treat it as your real deadline.
Step 5: carry back or carry forward the excess
If your harvested losses exceed your 2026 gains, the excess doesn't vanish — you can carry it back up to 3 years to offset past gains (which can generate a refund for those years) or forward indefinitely against future gains. The carry-back is the underused move: if you paid tax on gains in any of the last three years, this year's losses can claw some of it back.
Why this order: gains first (you need the target), losers second (the ammunition), the 61-day check third (the trap that voids the whole exercise), settlement deadline fourth (the calendar that ends it), carry rules fifth (what to do with the leftovers). Skipping straight to selling — the step everyone wants to start at — is how the superficial loss rule bites.
The traps, collected
- The TFSA/RRSP repurchase. Buying the same security in a registered account within 30 days of the sale kills the loss. This catches people every December.
- The spouse's account. Your spouse buying the identical security inside the window triggers the rule too.
- The December 31 sale. Trade date isn't the deadline — settlement date is. T+1 means the last practical sell day is at least a business day earlier.
- Harvesting inside registered accounts. There is no benefit — and no reporting — of capital losses inside an RRSP, TFSA, or FHSA.
- Forgetting the carry-back. Excess losses aren't wasted; they reach back 3 years or forward forever.
What success looks like
By your brokerage's December deadline, your taxable account holds no intentional unrealized losers, your 2026 gains are covered, your swap positions are in non-identical securities, and nothing was repurchased inside the 61-day window. Hand the trade confirmations to your accountant with your gains total — the rest is their arithmetic.