Capital Gain
Profit realized on the sale of a property (shares, assets, or other capital property) at a price above its tax cost. Only a portion of the gain is generally included in taxable income, depending on the rules in force on the sale date.
Definition
A capital gain is the difference between the sale price of a property and its adjusted cost base (ACB) — essentially, what the property originally cost, adjusted under the applicable tax rules.
In French-language Quebec documentation, you’ll see gain en capital used for the same concept.
For example, if you acquired the shares of your business for $100,000 and you sell them for $2 million, the economic capital gain is $1.9 million, before factoring in fees and more detailed tax rules.
Why the capital gain is central in a business sale
The sale of a business often generates a capital gain. How that gain is treated for tax purposes directly determines how much the seller keeps after tax.
How a capital gain is taxed
- The gain is calculated from the sale price, the ACB, and certain transaction fees.
- Only a portion of the gain is included in taxable income.
- The applicable inclusion rate depends on the rules in force on the sale date.
- Actual tax also depends on your province, your other income, the losses available to you, and any applicable deductions or exemptions.
Simplified example
On an economic gain of $1.9 million:
- the full gain isn’t automatically the tax payable
- you first determine the taxable portion under the rules in force at the time of the transaction
- you then apply the available deductions, including the Lifetime Capital Gains Exemption where it applies
Note: on a qualifying share sale, the Lifetime Capital Gains Exemption can substantially reduce — and sometimes eliminate — the tax on a portion of the gain.
What every seller should know
- A capital gain is often taxed more favourably than ordinary income, but the exact advantage depends on the rules in force at the time of sale.
- The structure of the transaction (share sale vs. asset sale) directly affects the tax treatment of the gain.
- Tax planning 12 to 24 months before the sale can meaningfully reduce the tax — consult a tax specialist with M&A experience.
- Tax rules change regularly — always check the rates, thresholds, and deductions that apply on the actual date of your transaction.