Key takeaway: The weeks before December 31 offer critical opportunities to reduce your 2026 tax bill and optimize registered accounts. Strategic RRSP contributions, TFSA top-ups, and capital gains timing can materially lower your tax liability and position you for stronger after-tax returns in 2027.

December 31 is more than a calendar milestone. For Canadian taxpayers, it marks the hard deadline for actions that affect your 2026 tax return. Missing these cutoffs means leaving money on the table or paying more tax than necessary. The five strategies below focus on high-impact moves you can execute in the final weeks of the year.

1. Maximize RRSP Contributions Before December 31 for Current-Year Deduction

While the official RRSP contribution deadline for the 2026 tax year extends to March 1, 2027, contributions made between January 1 and December 31, 2026 can be claimed as a deduction on your 2026 return or carried forward to future years. If you expect higher income in 2026 than 2027, making the contribution before year-end and claiming the deduction immediately can reduce this year’s tax bill (CRA, 2026).

Your 2026 RRSP contribution room is 18% of your 2025 earned income (up to the annual maximum of $32,490 for 2026, as of October 2026; verify current limits on the CRA website). Check your Notice of Assessment or CRA My Account for your exact available room. Contributions reduce taxable income dollar-for-dollar at your marginal rate, so a $10,000 contribution in a 43% marginal bracket saves $4,300 in tax.

If you lack the cash to contribute the full amount by December 31, consider making a partial contribution now and completing the remainder by the March deadline. Alternatively, borrow to contribute if the tax refund will cover the loan repayment, though this carries risk and should be modelled carefully.

2. Top Up TFSA to Shelter Future Growth Tax-Free

Unlike the RRSP, TFSA contributions do not generate a tax deduction. However, topping up your TFSA before year-end shelters the account’s 2027 growth and income from tax. Any dividends, interest, or capital gains earned inside the TFSA remain tax-free forever, and withdrawals do not trigger tax or affect income-tested benefits like OAS or GIS.

The 2026 TFSA annual limit is $7,000 (as of October 2026; confirm current limits with the CRA). Unused room from prior years carries forward, so your total available contribution room is the cumulative total since you turned 18 (or 2009, whichever is later) minus any contributions you have already made, plus any withdrawals from prior years (CRA, 2026).

Contributing on December 31 rather than waiting until January 1, 2027 gives your money one extra day of tax-sheltered growth, a trivial difference. The strategic reason to act before year-end is to deploy available cash while it is still in hand and to ensure the contribution is processed in the current year, avoiding any accidental over-contribution if your room calculation was incorrect.

3. Harvest Capital Losses to Offset Capital Gains

If you hold non-registered investments that have declined in value, selling them before December 31 crystallizes a capital loss that can offset capital gains realized earlier in 2026. Capital losses can also be carried back three years or carried forward indefinitely to offset gains in other tax years, making this a valuable long-term tax tool (CRA, 2026).

The superficial loss rule prohibits claiming a loss if you (or your spouse, or a corporation you control) repurchase the identical security within 30 days before or after the sale. To harvest the loss while maintaining market exposure, either wait 31 days before repurchasing, or immediately buy a similar but not identical security (for example, sell one Canadian equity ETF and buy a different one tracking a similar index).

Read also: Capital Gains Tax Changes in Canada: What Investors Need to Know

Tax-loss harvesting is most effective when you have realized gains in the current year or recent past years. If you have no gains to offset, the loss still carries forward and can shelter future gains, but the immediate tax benefit is zero.

4. Defer Capital Gains to 2027 If Income Is Lower Next Year

The reverse strategy applies if you expect lower income in 2027. Delaying the sale of appreciated investments until January 2027 shifts the taxable gain into the next tax year, when your marginal rate may be lower. This is particularly relevant for individuals retiring in early 2027, taking parental leave, or otherwise anticipating a material income drop.

Capital gains are 50% taxable (as of October 2026; tax legislation is subject to change, so verify current inclusion rates before acting). The taxable portion is added to your income and taxed at your marginal rate. If your 2026 marginal rate is 43% and your 2027 rate will be 29%, waiting to sell a $20,000 gain saves $1,400 in tax ($10,000 taxable gain, 14 percentage points lower rate).

This strategy assumes the investment’s value will not decline materially in the intervening weeks. Weigh the tax benefit against the market risk of holding through year-end.

5. Review Contribution Room and Correct Over-Contributions Before Year-End

RRSP and TFSA over-contributions trigger penalty taxes. The RRSP over-contribution penalty is 1% per month on the excess above $2,000, and the TFSA penalty is 1% per month on the full over-contribution amount with no buffer. These penalties compound quickly and continue until the excess is withdrawn (CRA, 2026).

Log into CRA My Account before December 31 to verify your RRSP deduction limit and TFSA contribution room. If you discover an over-contribution, withdraw the excess immediately to stop the penalty clock. The CRA may waive penalties if the over-contribution was unintentional and corrected promptly, but waiver is discretionary and not guaranteed.

Common over-contribution traps include forgetting employer pension adjustments (which reduce RRSP room), miscalculating cumulative TFSA room, or contributing after a spousal breakdown when room has been split. Double-check your records against the CRA’s official numbers.

Confirm Limits and Consult a Professional

Tax rules, contribution limits, and capital gains inclusion rates change annually. The figures cited above reflect October 2026 information; verify current amounts on the CRA website before acting. Year-end tax planning involves trade-offs specific to your income, marginal rate, investment horizon, and liquidity needs. For personalized advice, consult a Chartered Professional Accountant (CPA) or Certified Financial Planner (CFP).

The information in this article is educational and general in nature, and does not constitute personalized tax, investment, or financial advice. Tax rules are subject to legislative change.