Can my spouse claim half my business when we separate in Ontario?

In Ontario, your spouse cannot automatically "take half your business" the way the question implies, but the value of your business is almost certainly included in your net family property calculation. If your business increased in value during the marriage, that growth is part of what gets equalized.

The equalization system does not require you to hand over a share of the business itself. Instead, you calculate the value of the business as of the separation date, subtract its value as of the date of marriage (if you owned it before you married), and that net increase factors into the equalization payment. Your spouse may be owed a portion of that increase in cash or other assets, but you may be able to keep full ownership of the business and compensate your spouse in other ways.

Valuing a private business is often complex and contested. Common valuation approaches include looking at earnings, assets, or what the business could be sold for. Both spouses often retain independent business valuators, and the gap between their opinions can be significant.

If protecting your business in the event of separation is a concern, a marriage contract that specifies how the business will be valued — or excludes it entirely — is the most reliable protection.