Does buying a unionized business mean I inherit the current collective agreement's exact terms?

Generally, yes, if Ontario labour relations law's successor-rights provisions apply to your transaction. Where you're found to be continuing substantially the same unionized operation, you typically step into the existing collective agreement as it currently stands, on its existing terms, rather than being able to negotiate a fresh agreement immediately simply because ownership changed. The agreement continues to bind you as written until it either expires or is renegotiated through the normal collective bargaining process the parties would otherwise follow.

This surprises buyers who assume that acquiring a business gives them an opportunity to reset unfavourable terms right away. It generally doesn't — the collective agreement's wage rates, benefits, seniority provisions, and grievance procedures continue to apply to you exactly as they applied to the seller, and unilaterally changing them without going through proper bargaining channels can itself become a labour relations problem.

Understand the current agreement's actual terms and its expiry date before closing, since that timeline, not your closing date, is what determines when you'll have a real opportunity to negotiate changes. A Treadstone business lawyer can help you understand your obligations under the existing agreement.