What is subrogation and can my insurer sue someone on my behalf in Ontario?

Subrogation is the right your insurer gets, after paying your claim, to step into your shoes and pursue the person actually responsible for your loss to recover what it paid out - essentially, your insurer takes over your legal right to sue the at-fault party, up to the amount it paid you. This is common after property damage or liability claims where a third party's negligence caused the loss: the insurer pays you promptly under your own policy, then separately goes after the responsible party rather than making you wait for that recovery yourself.

Because the insurer is exercising your right, your policy typically requires you to cooperate - providing information, not releasing the at-fault party from liability, and not undermining the insurer's ability to recover. If your own loss exceeds what the insurer paid, you may also have a remaining personal claim against the responsible party for the uncovered portion, and how that interacts with the insurer's subrogated claim can get complicated. If you're approached to sign anything releasing a third party after an insured loss, it's worth checking with your insurer or a lawyer first, since it could interfere with a subrogation claim already underway.