Tax loss harvesting is the strategy whereby assets in non-registered accounts are sold to generate a capital loss¹. These losses can be used to offset capital gains, either this year, in previous years (up to three years back), or in future years (forever)².

Since CRA uses the settlement date of your asset sale, and since most (all ?) brokers take a day to settle a trade, this means to get your capital loss in fiscal 2025 you have to sell by December 30 to settle on December 31, the last business day of 2025.

1. After the current buoyant year in the markets, there’s probably not too many examples of this, but if you bought bonds in 2022…. ↩︎
2. All this and more detailed over at https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-return/completing-a-tax-return/personal-income/line-12700-capital-gains/capital-losses-deductions.html ↩︎