Most year-end tax bills are not decided in December. They are decided by what you did, or did not do, in the months before. By the time the year actually closes, most of the levers have already moved out of reach. The businesses that pay less tax are not luckier. They started planning while there was still time to act.
For a business with a December 31 year-end, Q4 is that window. Here are the moves worth reviewing now, while you can still do something about them.
Know your number before you plan around it
Every year-end tax move depends on one thing you cannot plan without: a reliable estimate of your taxable income for the year. You cannot decide whether to defer revenue, accelerate a purchase, or adjust compensation if you do not know roughly where you are going to land.
This is the unglamorous foundation of tax planning, and it is where most owners are stuck. If your books are current through Q3, you can project the full year with reasonable confidence and plan accordingly. If your books stop in the summer, you are planning blind, and most of the worthwhile moves are off the table. Getting your books current is not a side task to tax planning. It is the precondition for it.
Time your income and expenses deliberately
If your business has any control over when revenue lands or when deductible costs are incurred, the end of the year is when that control is worth using. Depending on whether you expect this year or next to be the higher-income year, you may want to pull a deductible purchase into this year or push it into next, or manage when certain revenue is recognized.
The point is that this is a decision, and decisions need lead time. A planned equipment purchase made deliberately before year-end is a different outcome than the same purchase made in a panic on December 30. The deliberate version is planning. The panic version is just spending.
Review owner compensation while you still can
For owner-managed corporations, the salary-versus-dividend mix is one of the larger planning levers, and it interacts with payroll, CPP, RRSP room, and your personal tax position. The details depend entirely on your situation and belong in a conversation with your tax advisor. What matters here is the timing. This is a Q4 conversation, because several of the mechanisms behind it have to be executed before the year closes. Left to December, the options narrow.
Check your instalments against reality
By Q4 you have most of the year’s actual results in hand, which makes it the right time to compare what you have paid in tax instalments against what you are actually going to owe. If you have underpaid, you can still top up a remaining instalment to reduce the interest the CRA would otherwise charge. If you have overpaid, you have cash tied up that you could be using. Either way, this is a check worth doing before year-end, not a surprise to absorb when the assessment arrives.
Do not forget the provincial and credit landscape
Tax planning is not only federal. Provincial rates and credits shift, and 2026 has seen movement worth a conversation with your advisor, including changes to certain provincial rates and investment credits. The specifics depend on your province and your activity, and they change, so this is a prompt to ask the question rather than a rule to apply. The general principle holds: a credit you qualify for is only useful if someone identifies it in time to claim it.
Get the documentation in order now
Some of the most common year-end tax problems are not strategy failures. They are documentation failures. A deduction you are entitled to but cannot support is a deduction you may lose. Q4 is the time to make sure the backup exists and is organized, while the year is fresh, rather than reconstructing it under deadline pressure in the spring.
This is another place where clean monthly books pay off directly. When your records are reconciled and current all year, year-end documentation is a matter of pulling files, not rebuilding them.
The Q4 checklist
Get your books current through Q3 so you can project the year. Estimate your taxable income. Review the timing of any income and expenses you control. Have the compensation conversation with your advisor while the mechanisms are still available. Reconcile your instalments against your projected liability. And get your documentation organized before the year closes.
The common thread is that all of it depends on knowing your numbers in time to act on them. If your books are not current enough to plan from, that is the first thing to fix. Book a free Diagnostic and we will get you to a position where year-end planning is actually possible.
