When can a defendant ask the court to order the plaintiff pay security for costs in Ontario?

A security for costs motion asks the court to order a plaintiff to post money or other security upfront, to guarantee that if the defendant wins and is awarded costs, there's something to collect from. Ontario courts will consider this where there's a real concern the plaintiff won't be able to pay a costs award later — for example, where the plaintiff lives outside Ontario and has no assets here to enforce against, where a corporate plaintiff appears to have insufficient assets in the province, or where the plaintiff has a history of unsuccessful, similar claims. It is not available simply because a defendant thinks the plaintiff is likely to lose.

The court weighs whether ordering security would unfairly block a legitimate claim from being heard, particularly where a plaintiff genuinely can't afford it, against the defendant's interest in not winning a costs award it can never actually collect. If security is ordered, the plaintiff generally must post it before the action can continue, and failing to do so can result in the claim being dismissed. This motion is more common in cases involving out-of-province or foreign plaintiffs, or thinly capitalized corporate parties, than in ordinary Ontario resident-versus-resident disputes.