Will my group insurance coverage have a gap while the sale is being finalized?

It's a real possibility, and it's one of the more practical things worth confirming directly rather than assuming will sort itself out. Your continuous service is protected under Ontario's continuity-of-employment rules, but the specific group insurance policy you're covered by is a separate contract between your employer and an insurer — it doesn't automatically transfer or continue without interruption just because your employment does.

If the new owner is switching to a different insurer or plan, there can be a genuine administrative gap between when the seller's policy stops covering you and when the buyer's plan actually takes effect, even where the transition is handled reasonably well. This matters practically for things like ongoing prescriptions, scheduled treatments, or claims in progress, which can get caught in the middle of a switchover if you're not paying attention to timing.

Ask HR or whoever's coordinating the transition, specifically and in writing, exactly when the old coverage ends and the new coverage begins, and whether there's any gap at all — and if there is a gap, ask what options exist to bridge it, such as timing a prescription refill or a claim submission around the actual dates rather than assuming continuous coverage.