Tax-Loss Selling Canada: The 2026 Deadline Is December 30
Most investors write December 31 in the calendar and assume that is the line. For tax-loss selling in Canada that is wrong by one day, and the reason is settlement.
A sale only lands in the 2026 tax year if the trade settles inside 2026. December 31, 2026 is a full trading day on the TSX, but a trade placed that day settles on Monday, January 4, 2027. That makes Wednesday, December 30, 2026 the last trade date of the year that settles in 2026, and the real deadline for harvesting a loss against a 2026 gain.
Below: the settlement math behind that date, what a harvested loss is worth in cash, what happens to the part you cannot use this year, and two errors that ruin the exercise. Rates and thresholds here are 2026 figures, data as of September 19, 2026.
The last trade that counts for 2026
The TSX closes early on Christmas Eve, Thursday December 24, at 1:00 PM, shuts for Christmas Day on Friday December 25, and closes again on Monday December 28 in lieu of Boxing Day. January 1, 2027 is closed. Those four dates bend the settlement calendar in the one week of the year when most harvesting happens.
TMX publishes a holiday settlement schedule, and it applies to both CAD and USD traded securities. It puts a December 24 trade on a December 29 settlement and a December 31 trade on a January 4, 2027 settlement. December 29 and December 30 are not exceptions, so they settle on the ordinary next business day basis.
| Trade date | Settles | Counts for |
|---|---|---|
| Thursday, December 24 (1:00 pm close) | Tuesday, December 29, 2026 | 2026 |
| Friday, December 25 | Market closed | Not applicable |
| Monday, December 28 | Market closed | Not applicable |
| Tuesday, December 29 | Wednesday, December 30, 2026 | 2026 |
| Wednesday, December 30 | Thursday, December 31, 2026 | 2026 |
| Thursday, December 31 | Monday, January 4, 2027 | 2027 |
Source: TMX Settlement Schedule for 2026 Holidays, and the TSX 2026 stock market holiday calendar.
Why settlement rather than the trade ticket? Because of the slip. The CRA’s instruction to the broker filling out a T5008 is to “Enter the month and day on which the transaction was completed (the settlement date).” Sell on December 31 and the slip the CRA receives carries a 2027 date.
What a harvested loss is worth
Only half of a capital loss is deductible, because only half of a capital gain is taxable. Section 38(a) of the Income Tax Act puts it this way: “a taxpayer’s taxable capital gain for a taxation year from the disposition of any property is ½ of the taxpayer’s capital gain for the year.” The mirror of that taxable capital gain is the allowable capital loss, and the inclusion rate for 2026 is one half.
The CRA’s Capital losses page sets out what happens next: “Generally, if you had an allowable capital loss in a year, you have to apply it against your taxable capital gain for that year. If you still have a loss, it becomes part of the computation of your net capital loss for the year.”
That first sentence matters more than it looks. The current year offset is not optional. You do not get to bank a fresh loss while paying tax on this year’s gains because next year looks richer. The loss hits 2026 gains first, and only the remainder becomes a net capital loss.
And a net capital loss offsets taxable capital gains only. It does not reduce employment, self-employment, pension or interest income. A year with a large harvested loss and no gains produces no immediate tax saving at all.
A worked example
Take an Ontario resident with $120,000 of taxable income before capital gains, a $12,000 capital gain already realized in 2026, and a position sitting on a $30,000 unrealized loss that gets sold before the deadline.
At $126,000 of taxable income the federal bracket from $117,045.01 to $181,440 applies at 26%, and the Ontario bracket from $107,785.01 to $150,000 at 11.16%. Then Ontario adds surtax. Per CRA T4032ON, January 2026 edition, “where the basic provincial tax payable is greater than $7,446, the surtax is 20% of the basic provincial tax payable over $5,818, plus 36% of the basic provincial tax payable over $7,446.” Basic Ontario tax here, after the $12,989 Ontario basic personal credit, is $9,029.65, which clears the higher threshold, so both layers apply. The surtax alone is $1,212.44.
Combined, the federal and Ontario marginal rate at $126,000 is 43.41%, which puts the effective rate on a capital gain at 21.705%. If you want the mechanics behind why a gain is taxed at half the rate on your salary, and how dividends and interest differ again, our guide to how investment income is taxed in Canada works through each type.
Now the harvest. The $12,000 gain is a $6,000 taxable capital gain. The $30,000 loss is a $15,000 allowable capital loss. The allowable loss applies against the taxable gain first, wiping out the $6,000 and leaving a $9,000 net capital loss for 2026.
Tax payable with the gain and no harvest: $32,760.62. Tax payable with the loss applied: $30,156.04. The harvest saves $2,604.58 in 2026, which is the $6,000 of taxable capital gain removed at a 43.41% marginal rate.
The leftover $9,000 is the interesting part
The $9,000 does not expire. It can go back against taxable capital gains in any of the three preceding years, which for a 2026 loss means 2023, 2024 and 2025, or forward with no time limit. And you get to aim it: “When you carry back your net capital loss, you can choose the year(s) to which you apply the loss.”
That choice is worth real money, because the refund comes at the marginal rate of the year you point it at, not the year you harvested in.
| Taxable income in the carryback year | Marginal rate | Refund on $9,000 |
|---|---|---|
| $60,000 | 29.65% | $2,668.50 |
| $90,000 | 29.65% | $2,668.50 |
| $126,000 | 43.41% | $3,906.86 |
| $200,000 | 47.97% | $4,317.26 |
Caption: Ontario resident, 2026 rates. Federal and Ontario brackets from the CRA’s current year tax rates and income brackets; Ontario surtax from CRA T4032ON, January 2026.
The same $9,000 is worth $2,668.50 or $4,317.26 depending on the year it lands in. Note that $60,000 and $90,000 return the identical 29.65%, because Ontario’s surtax has not started at either income. With losses banked from several years, the CRA sets the order: “Apply net capital losses of earlier years before you apply net capital losses of later years.”
What a carryback does not do
This is the least obvious point in the exercise, and the CRA states it plainly: “When you apply a net capital loss back to a previous year’s taxable capital gain, it will reduce your taxable income for that previous year. However, your net income, which is used to calculate certain credits and benefits, will not change.”
Taxable income moves. Net income does not. A carryback refunds income tax and nothing else. It will not restore an OAS payment clawed back in the earlier year, and it will not retroactively lift an income-tested benefit. Anyone harvesting to undo a clawback is solving the wrong problem.
The paperwork
Two forms, and neither is an amended return.
The loss itself is registered on Schedule 3, filed with the 2026 return. That is what puts the net capital loss on the CRA’s records and keeps it available for future use, whether or not you use it now.
The carryback request is Part 5, “Net capital loss for carryback”, on Form T1A, Request for Loss Carryback. The same form works out how much is left to carry forward. The CRA is unambiguous on the alternative: “Do not file an amended Income Tax and Benefit Return for the year you want to apply the loss.”
Two traps before you hit sell
Your adjusted cost base is not the number on the slip. The CRA warns individuals directly about box 20 of the T5008: “The amount in box 20 may or may not reflect your adjusted cost base (ACB) for the purpose of determining the gain or loss from the disposition of the security.” The duty to adjust it sits with you. If you bought in tranches, or hold the same security at two brokers, the ACB is averaged across every unit you own. Harvesting against the wrong ACB harvests the wrong number, so keep the running average yourself: our adjusted cost base calculator does the averaging.
The 30 day rule. Selling at a loss and buying the same security straight back denies the loss under the superficial loss rules, and the repurchase window extends on both sides of the sale. It has more moving parts than one paragraph carries, so read our explainer on the superficial loss rule before planning any sell and rebuy.
The bottom line
Every rate and threshold above is a 2026 figure for an Ontario resident, current as of September 19, 2026. Other provinces set their own brackets and, in several cases, no surtax at all, so the dollar results differ outside Ontario even though the deadline and the carryback rules do not.
The binding constraint on tax-loss selling is a settlement date in the thinnest week of the year. Wednesday, December 30, 2026 is the last trade that lands in the 2026 tax year. The question that date forces is whether the position still deserves your capital, not whether it deserves a tax deduction, and nothing about that judgment gets easier by waiting for the deadline.
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