Can a marriage contract protect my business if the marriage ends in Ontario?

Yes. A marriage contract is one of the most effective tools for protecting a business from equalization claims if a marriage ends. Under the Family Law Act, the net value of a business owned by either spouse at the date of separation is included in that spouse's net family property and is subject to equalization. A marriage contract can change this result by specifying that the business or a business interest is excluded from equalization, or by setting a fixed formula for how any increase in business value will be treated.

Without a contract, the non-owning spouse can claim half the net increase in the business's value from the date of marriage to the date of separation. Valuing a business is often contentious and expensive. A contract that addresses this upfront — for example, by agreeing that the business value at the date of marriage (plus any increase) remains with the owning spouse — avoids costly valuation disputes later.

The business's financial statements and any valuation reports at the time of signing should be attached to the agreement or referenced in it to establish the baseline clearly. Both parties should have independent legal advice from lawyers who understand business valuation issues. If the business has multiple shareholders or is a professional corporation, additional complexities arise that a lawyer can help navigate.